Introduction to:
Problem Oriented Approach in
Pediatric Radiology
Introduction
Pediatric Radiology is the application of diagnostic radiology in the understanding ,diagnosis, therapy, and follow up of diseases of infants and children.
To minimize radiation risks and maximize benefits from any imaging examination ,the procedure should be tailored to the specific clinical problem.
An algorithm for each clinical presentation , will help to reach a “definite “ diagnosis ,with the least radiation exposure and cost .
The referring physician ,as well as the pediatric Radiologist ,have the duty to take PROBLEM ORIENTED
DECISIONS ,which will decide ,which techniques will be used or omitted in any given clinical situation ,so as to reach the appropriate diagnosis.
I-Thorax
CXR-showing a large mediastinal mass lesion .
1. Patient with a chest mass.
The clinical problem :
The discovery of a chest mass on CXR is a common finding which can happen in the course of investigation for a tachypneic child ,signs of SVC obstruction ,coughing ,chest infection ,or incidentally.
The need for identifying a normal thymus is needed.
The location of chest mass is necessary to build a working differential diagnosis.
Role of Radiology:
An approach includind CXR with chest US has been proposed by some authors .
The technique depends on examining the chest through suprasternal ,parasternal and sub-xiphoid windows.
The main role of U.S. is :
1. Identify a normal thymus.
2. Differentiate between a cystic or solid mass lesions.
3. Study of the cystic lesion –which is most likely bening-regarding its size ,wall ,contents ,etc..
4. Evaluate the solid lesion regarding its site ,size ,borders ,presence or absence of necrosis ,vascularity ,etc..
5. guide for interventional procedure (biopsy or aspiration for peripheral lesion
Etiology:
I-Mediastinal masses.
II-Chest wall masses:
-Normal structures at pleural surface
Location Causes
Soft tissue tumors
Lymphangioma
Cystic Hygroma
Extrapleural –
intrathoracic Mesenchymoma-Lipoma
Rhabdomyosarcoma
Bony thorax tumors
Generalized bone diseases :Neurofibromatosis-Multiple hereditary exostosis,
Benign causes:fibrous dysplasia-osteochondroma-eosinophilic granuloma-Aneurysmal bone cyst.
Malignant:Ewing Sarcoma- PNET-chondrosarcoma-Osteosarcoma
Etiology Anterior Mediastinum Middle Mediastinum Posterior Mediastinum
Congenital Thymic cyst
Morgagni Hernia
Foregut cyst
Hiatal hernia-achalasia
Foregut cyst.
Lateral meningocele
Bochdaleck Hernia
Inflammatory Mediastinitis.
Lymohadenopathy
Mediastinitis.
Lymphadenopathy
+spinal inflammatory
diseases
Neoplastic Lymphoma-Leukemia
Germ Cell tumor.
Teratoma
Lymphoma-Leukemia Neurogenic
tumours(neural crest or
peripheral nerve
Tumors ).lymphoma-
Leukemia-
Phaechromocytoma.
Traumatic Haematoma
Thymic Hemorrhage
Hematoma.
Diaphragmatic rupture
Spinal fracture
Vascular Annomalous vessel Aneurysm.
Great vessels anomaly
Aortic aneurysm
Dilated azygous vein
Miscelaneous Histiocytosis
Sarcoidosis
Pancreatic pseudocyst-
Histiocytosis-sarcoidosis
Extramedullary
Haematopoiesis.
Metastatic: Neuroblastoma-Leukemia
III-Lung Masses :
Location Causes
Pleural Metastasis-Leukemia-Lymphoma-Askin tumor
Parenchymal
Primary:
Benign:Bronchogenic cyst-Sequestration-Round pneumonia-hamartoma-bronchial adenoma. Malignant:Sarcoma-
Pulmonary Blastoma
Secondary:
Benign:Papillomatosis Malignant:Wilm’s tumor,Osteosarcoma,etc.
B-Flow of thinking : 5 questions to ask.
1.Location 2.Density 3.enhancement 4.Morphology 5. Associations
(Wall/med/lung) (air/fat/calcification) ( border/size/shape) (displacement/bony
Destruction)
2. Patient with upper Airway Obstruction
CXR:Church steeple sign denoting Croup
A-Etiology :
The differential diagnosis of upper air way obstruction depends upon :the age of presentation (neonatal ?older children),associated findings (fever/nasal obstruction/stridor),history of foreign body inhalation.
Mechanism Causes
Congenital
Choanal atresia -micrognathia-ectopic thyroid-laryngomalacia-laryngeal ,subglottic tracheal
stenosis-nasal encephalocele.
Inflammatory
Adenoids- retropharyngeal abscess-croup-epiglottitis-
Masses
Laryngeal,aryepiglottic,retention,or epiglottic cysts-cystic hygroma-hemangioma-papilloma-
Rhabdomyosarcoma-dermoid / teratoma-Nasopharyngeal mass(Angiofibroma)
Traumatic
Foreign body-hematoam-radiation-thrermal injury.
Miscellaneous
Tracheomalacia-vascular ring-angioneurotic edema
Role of Imaging:
1.Croup:
Pathophysiology: The cells of the respiratory epithelium are infected following viral inhalation. Inflammation is
diffuse in the involved airway.
X-ray diagnosis: Frontal neck radiograph: The lateral walls of the subglottic larynx normally are convex or shouldered . Wall edema in croup narrows this space with loss of lateral convexity, creating a steeple shape below the vocal cords The narrowing may extend for 5-10 mm below the vocal cords.
2.Epiglottitis: Pathophysiology: Epiglottitis causes inflammation and swelling of the epiglottis, vallecula, arytenoids, and
aryepiglottic folds. As the tissues swell, they protrude downward and over the glottic opening, making breathing
difficult.
X-ray diagnosis: In epiglottitis, images show diffuse soft-tissue swelling with enlargement of the epiglottis and also of
the normally thin aryepiglottic folds. One should look for an enlarged epiglottis (thumbprint sign), thickened
aryepiglottic folds, and ballooning of the hypopharynx, usually with normal subglottic structures .
CXR:Bilateral consolidation patches-Broncho-pneumonia
3. Patient with chest Infection
A-Etiology :
1. Viral(Adeno virus-Haemophylis Influenza –Respiratory syncitial virus)
2. Bacterial (streptococcal-Staphylococcal-Klebsiella)
3. Fungal(aspergillosis)
4. Tuberculous.
5. Mycoplasma.
6. Amebic.
B-Complications:
1. Empyema.
2. Pulmonary abscess.
3. Bronchopleural fistula.
4. Septic embolization.
Large pleural collection in left hemithorax –post staph pneumonia-Empyema.
Ultrasonic examination revealing loculated pleural effusion.
4. Patient with recurrent/chronic pulmonary problems
A-Etiology :
Extensive list for the causes of chronic /recurrent lung infections are present.
Mechanism Causes
1. Aspiration
CNS malformation-cerebral tumors-
Tracheo-esophageal fistula-Reflux
2.Anomaly
Congenital lobar emphysema-
Sequestration-Tracheobronchial tree
anomalies(tracheal bronchus-
stenosis-atresia)-bronchogenic cyst.
3.Allergy.
Astham- Loeffler pneumonia-allergic
alveolitis
4.Systemic disease.
Cystic fibrosis
5.Immunodeficiency.
Prematurity-AIDS-Neutropenia
6.Physical agents.
Foreign body-Drugs-radiation-
Bronchopulmonary dysplasia
7.Neoplasm.
Leukemia-Lymphoma-Histiocytosis
8.CVS
Left to right shunt -PA stenosis-
vascular ring
9.specific Infections.
TB-Mycoplasma-Bronchiectasis
10.Miscellaneous
Interstitial Pneumonia-Collagen
vascular disease-Alveolar
proteinosis-sarcoidosis.
B-Role of Radiology :
The role of radiology is 3 folds :
1 .Evaluate the present X-ray.
Look for :
The presence and distribution of opacities,Pleural involvement ,Lymph nodal swellings ,pulmonary vascularity ,soft tissue involvement , bony structures .
2.Review of previous films.
Look for:
Are the lesion stable in the same location (Sequestration ?)
Are they present always in upper lobe (aspiration ? )
Are they changing in location (Immunodeficiency ?)
3.Perform esophagogram.
Look for :
1. Reflux of gastric contents.
2. Abnormal peristalsis-Compression of esophagus by a mass ,vascular ring.
3. Tracheo-esophageal fistula.
4. Hiatal Hernia
Left basal pulmonary lesion with systemic aterial supply (2)..Pulmonary sequestration
5.Neonate with respiratory distress
CXR :RDS –Bilateral Opacification with air bronchogram.
Etiology:
1. Respiratory distress syndrome.
2. Congenital Diaphragmatic Hernia.
3. Congenital Cystic Adenomatoid Malformation.
4. Congenital Lobar Emphysema.
5. Lung agenesis /hypoplasia.
6. Tracheal stenosis/atresia.
7. Pulmonary sling.
8. Vascular ring.
Role of imaging
1.Congenital Cystic adenomatoid Malformation:
Pathogenesis and pathophysiologic features: CAM is believed to result from focal arrest in fetal lung development
before the seventh week of gestation secondary to a variety of pulmonary insults.
Types:
Type I lesions, the most common, are composed of 1 or more cysts measuring 2-10 cm in diameter.
Type II lesions are characterized by small relatively uniform cysts resembling bronchioles
Type III lesions consist of microscopic, adenomatoid cysts, and are grossly a solid mass without obvious cyst
formation.
Radiographic findings:
The pattern in the lung demonstrates multiple radiolucent areas that vary greatly in size and shape. Cysts are separated
from each other by strands of opaque pulmonary tissue.
The involved lung may appear honeycombed or spongy, but occasionally, 1 large cyst may overshadow the others. Air
trapping within cystic spaces can cause rapid enlargement of the CAM
CT findings:
Areas of small cysts (<2 cm in diameter) appearing with other abnormalities (a larger cystic area, consolidation, or low
attenuation) are the most frequent findings.
Multiple large cystic lesions (>2 cm in diameter) are seen alone or with other abnormalities (areas of small cysts,
consolidation, or low attenuation).
Low-attenuation areas are clusters of microcysts.
Air-fluid levels can be seen in some cysts. These lesions may be predominantly type I, type II, or a combination of
both.
MRI findings:In CAM, prenatal MRI findings on T2-weighted images have been reported. CAMs appear as
intrapulmonary masses with increased signal intensity on T2-weighted images. Type III CAM lesions have moderately
high signal intensity.
Ultrasonic diagnosis:
Partially cystic partially echogenic masses are characteristic of type I or type II lesions. The size or dimension of the
cysts distinguishes the 2 types. Type III lesions may be large and entirely echogenic.
Chest X-ray revealing multiple basal lung cysts (CCAM)
CT chest :right basal cystic lesions-CCAM
2.Congenital lobar emphysema:
Pathophysiology: Overdistension of the airspaces within a pulmonary lobe is associated with air trapping and
compressive changes in the remainder of the lung . Mediastinal shift away from the increased volume results in
compression of the contralateral lung. CLE almost always involves one lobe, with rates of occurrence as follows:
Left upper lobe - 41%
Right middle lobe - 34%
Right upper lobe - 21%
X-ray findings: A large, hyperlucent lung with attenuated but defined vascularity is observed. Compressed remaining
lung on that side, flattened hemidiaphragm, and widened intercostal spaces also are seen. An involved lung is seen
herniated across the anterior midline.On a lateral view, the heart is displaced posteriorly with retrosternal lucency
representing an anteriorly herniated lobe .
CXR:large right basal cystic lesion.
CT rvealed area of hyperlucency :Congental Lobar Emphysema
CT findings: CT scan shows a hyperlucent, hyperexpanded lobe (attenuated but intact pattern of organized vascularity)
with midline substernal lobar herniation and compression of the remaining lung. Usually, the mediastinum is
significantly shifted away from the side of the abnormal lobe .
3.Respiratory distress syndrome :
Pathophysiology: RDS is the result of anatomic pulmonary immaturity and a deficiency of surfactant. Pulmonary
surfactant synthesis, in type II pneumocytes, begins at 24-28 weeks of gestation, and gradually increases until full
gestation. Pulmonary surfactant decreases surface tension in the alveolus during expiration, allowing the alveolus to
remain partly expanded, thereby maintaining a functional residual capacity.
In premature infants, an absence of surfactant results in poor pulmonary compliance, atelectasis, decreased gas
exchange, and severe hypoxia and acidosis.
X-ray diagnosis:
The radiologic spectrum of RDS ranges from mild to severe and is generally correlated with the severity of the clinical
findings.In the early stages of the disease, notable air bronchograms are lacking because the major bronchi lie in the
more anterior portions of the lungs and because alveolar atelectasis tends to involve the dependent areas of the lungs,
which are posterior in recumbent infants. However, a bubble appearance, which represents overdistended bronchioles
and alveolar ducts, can be observed. As RDS progresses, the reticulogranular pattern becomes prominent due to
coalescence of the small atelectatic areas. This coalescence leads to larger areas of increased lung opacity. As the
anterior portions of the lung become involved with microatelectasis, the granularity becomes uniformly distributed, and
air bronchograms can be seen. With increasing severity of disease, progressive opacification of the anterior portions of
the lungs cause obscuration of cardiac silhouette and the formation of prominent air bronchograms. With severe
disease, the lungs appear opaque and display prominent air bronchograms, with total obscuration of cardiomediastinal
silhouette.
CXR :respiratory distress syndrome
Complications:
1.Pulmonary interstitial emphysema:
PIE can be symmetrical, asymmetrical, or localized to 1 portion of a lung. Peripheral PIE can produce subpleural blebs and ultimately rupture into pleural space to produce pneumothorax (usually tension pneumothorax), or they can extend centrally to produce pneumomediastinum or pneumopericardium. Because infants are supine and because air rises to the highest point of the thorax, the pneumothorax is located paramediastinally, resulting in the sharp mediastinum sign, whereby the mediastinum/heart is sharply outlined by adjacent free air rather than aerated lung tissue.
CXR :Pulmonary interstitial emphysema
2.Bronchopulmonary dysplasia:
After days of ventilatory support, interstitial fibrosis results from the cumulative effect of therapeutic insult to the pulmonary parenchyma. This fibrosis is often accompanied by exudative necrosis and a honeycomb appearance of the lungs on chest radiography. The honeycomb appearance represents focally distended alveolar groups in a scarred, and immature lungs.
CT chest : ARDS in NICU patient with difficult extubation
II –Body
1. Vomiting
Digestive origin Extra digestive origin
Frequent Rare Infectious Otitis media - Labyrinthitis-Pneumonia-UTI
Congenital
hypertophic Pyloric
stenosis
Microgastria Neurological Cerebral
tumors,hydrocephalus,Abscess,hematoma
Antral Dyskinesia Antral Diaphragm Toxic Lead poisoning-Chemotherapy-Vitamin A&D
poisoning
Intussusception. Midgut volvulus Metabolic Fructosemia-Galactosemia-Tyrosinemia-
Adrenal insufficiency
Hirschprung disease Preduodenal portal
vein
Psychic Anorexia
Gastroenteritis Ladd’s Band
Acute Appendicitis Gastric or duodenal
Ulcer
1.Congenital Hypertrophic Pyloric stenosis: Pathophysiology: Full-thickness biopsies demonstrate both hypertrophy and hyperplasia of the circular muscle layer of
the pylorus.
Sex: Male-to-female ratio is 4-6:1.
Age: HPS most commonly is seen in infants aged 3-6 weeks
Imaging:
1. Ultrasonic diagnosis ;
US examination showing CHPS: note thich muscular layer and elongated canal
Target sign on transverse images of the pylorus
Muscle thickness of >3mm
Pyloric channel length greater than 17 mm
Pyloric thickness (serosa to serosa) of 15 mm or greater
Failure of the channel to open during a minimum of 15 minutes of scanning
Retrograde or hyperperistaltic contractions
Antral nipple sign, a prolapse of redundant mucosa into the antrum (creating a pseudomass)
2.Intussusception:
Role of imaging :
Abdominal radiograph:
Look for dilated small bowel and absence of gas in the region of the cecum . Occasionally, a mass impression within the colonic gas indicates an intraluminal mass created by the intussuscepting loop.
Abdominal radiograph :intususception transverse colon
Ultrasound Transverse: Ultrasound (US) shows a mass with a swirled appearance of alternating sonolucent and hyperechoic bowel
wall of the loop-within-a-loop.
Longitudinal: US of the mass shows a submarine sandwich-like appearance of the intussuscipiens and the
intussusceptum. There appear to be multiple layers, which represent the walls of the intussuscepted bowel loops .
Ultrasonic examination showing Donut sign of intususception
3.Mid gut Volvulus: Malrotation is caused by incomplete rotation (<270° of counterclockwise rotation occurring in weeks 5-12).
This group of disorders can be divided into different categories:
Nonrotation (0° to <90° of counterclockwise rotation occurring before 6 weeks)
Reverse rotation (abnormal rotation >90° and <180° causing obstruction or reversal of the normal duodenal/SMA relationship, occurring in weeks 6-10)
Malrotation most often associated with malfixation (>180° and <270° of counterclockwise rotation, occurring after 10 weeks)
Clinical Details: Malrotation with midgut volvulus classically presents in the neonate with bilious vomiting and high intestinal obstruction..
Older children with malrotation may show failure to thrive, chronic recurrent abdominal pain, malabsorption, or other vague presentations.
Radiological diagnosis:
1.UGI studies:
Findings of a UGI series in malrotation include the following:
DJJ displaced downward and to the right on the frontal view
An abnormal course of the duodenum on lateral view
An abnormal position of the jejunum (lying on right side of abdomen) .
In malrotation with midgut volvulus, findings also include the following:
A dilated, fluid-filled duodenum
A proximal small bowel obstruction
A "corkscrew" pattern (proximal jejunum spiraling downward in right or mid upper abdomen in midgut volvulus.
Mural edema, thick folds
UGI Typical corkscrew appearance of midgut volvulus
2. Ulrasound:
The "whirlpool sign" on color Doppler shows mesentery and flow within the SMV wrapping around the SMA (in a clockwise direction), indicating malrotation with volvulus. A dilated, fluid-filled duodenum frequently is seen in patients with obstruction without volvulus. However sensitivity and specificity are low compared to the UGI series; therefore, a UGI examination is mandatory to confirm the diagnosis
whirlpool sign" on color Doppler .
2- Abdominal mass
Etiology: Abdominal or pelvic masses are comon paediatric clinical problems.
The radiologist must be aware of the clinical presentation of the patient as well as his age.
The radiological examination depend mainly on:
1. Abdominal X-ray without preparation.
2. Ultrasonography.
Orientations:
1. Topographic localization .
2. Structural orientaion.
3. Associated lesions.
Abdominal Lesions :
I-Intraperitoneal Lesions :
� Causes before 6 months : Haemangioendothelioma- Pepper Syndrome
� Causes at any age :
1. Hepatic masses :hepatoblastoma.
2. Splenic masses :cysts
3. Cystic masses:
4. Ovarian masses.
5. Lymphomatous masses
II-Retroperitoneal Lesions :
Pillars of diagnosis :
1. Age.
2. structure (ultrasonic and CT)
3. Renal or adrenal origin.
Causes :
A-Renal : Unilateral :
Wilm’s tumour ,mesoblastic nehroma,Multiloclar cystic nephroma.
Bilateral :
Angiomyolipoma,nephroblastomatosis,lymphoma ,metastasis.
B-Adrenal:neurblastoma.
C-Lymphadenopahties :
Pelvic lesions
I-Neonatal period :
Girls :Ovarian cyst-Hydrometrocolpos.
Boys :PUV causing bladder distension.
Any sex:Teratoma-Meningoceles-pelvic neuroblastoma.
II-Post neonatal period:
1. Ovarian cyst.
2. Rhabdomyosarcoma.
3. Urinary bladder diverticulum.
4. Pelvic Abscess.
5. Bony tumours.
6. Nodal swellings.
1.Neuroblastoma:
Pathophysiology: Neuroblastomas arise from primitive neural crest cells that differentiate to form the sympathetic
nervous system.
Imaging:
Ultrasound:
Ultrasonography can be used as a screening tool for detecting abdominal or pelvic masses in children
Neuroblastomas appear as an inhomogeneously echogenic mass on sonograms. Calcifications typically appear as focal
brightly echogenic areas in the mass
CT findings: CT is the modality most commonly used to diagnose and stage neuroblastomas. CT can show the organ
of origin, extent of the tumor, lymphadenopathy, metastases, and calcifications. About 80-90% of neuroblastomas show
stippled calcifications on CT.
Neuroblastomas often encase or compress adjacent blood vessels. Neuroblastomas rarely invade into the lumen of
blood vessels.
The tumors often appear lobulated and typically have a heterogeneous appearance on contrast-enhanced CT. There are
areas of low attenuation in the mass secondary to necrosis and hemorrhage. CT is good for detecting lung metastases
and focal liver metastases (which appear as focal hypoattenuating and poorly enhancing masses). Bone-window
settings should always also be examined to assess for skeletal metastases.
MRI findings:
Neuroblastomas are typically hypointense on T1-weighted images and hyperintense on T2-weighted images. When
contrast material is administered, the tumor exhibits inhomogeneous enhancement. Calcifications appear as signal
voids on MRIs. Hemorrhagic areas often appear bright on T1-weighted images. Bone-marrow disease appears bright
(hyperintense) and heterogeneous on T2-weighted images and dark (hypointense) on T1-weighted images. Diffuse liver
metastases appear bright on T2-weighted MRIs.
Nuclear medicine:
Iodine-131 metaiodobenzylguanidine (MIBG) and iodine-123 MIBG are used to identify sites of primary neuroblastomas. Tumors that contain sympathetic tissue, such as neuroblastomas, ganglioneuroblastomas, ganglioneuromas, medullary thyroid carcinomas, pheochromocytomas, and carcinoids, take up MIBG.
Another isotope that can be used in detecting primary neuroblastomas is indium-111 pentetreotide, which is a
somatostatin analog.
Axial T2-weighted MRI demonstrates extradural extension into the spinal canal. 3-Patient with Urinary Tract Infection
Definition :
Pure growth of > 100 000 organism/ml urine
Etiology:
1. Vesicoureteric reflux.
2. Obstructive uropathy.
3. Reflux nephropathy and scar formation.
4-Neonate with Abdominal wall defects Etiology :
1. Omphalocele.
2. Gastroschisis.
3. Cloacal exstrophy (Omphalocele-Exstrophy of urinary bladder-Imperforate anus-meningeomyelocele )
4. Pentalogy of Cantrell :Omphalocle-Ectopic heart-Bifid sternum-Anterior diaphragmatic hernia-Pericardial defect )
1.Gastroschisis:
Pathophysiology: Controversy exists regarding the cause of gastroschisis. Some authorities suggest that the defect is
caused by abnormal involution of the right umbilical vein, resulting in rupture of the anterior abdominal wall at a point
of weakness. Others suggest that gastroschisis results from rupture of an exomphalos.
Another theory for etiology of gastroschisis is premature interruption of the right omphalomesenteric artery, which
results in ischemic injury to the anterior abdominal wall through which herniation of abdominal contents occurs.
Effects: Because the herniated bowel is bathed by amniotic fluid, both maternal serum and amniotic fluid AFP levels are elevated, more so than in exomphalos. Later in pregnancy, bowel obstruction, peritonitis, bowel
perforation, and fetal growth restriction may occur secondary to nutrient loss through exposed bowel.
Ultrasound findings: Findings include exteriorized bowel in relation to the anterior abdominal wall, multiple loops
of bowel, and a thickened bowel floating freely in the amniotic fluid. The bowel can be identified by its characteristic
sonographic pattern.
Because no covering is present around the bowel loops; the bowel loops of a gastroschisis result in a mass with irregular edges.
Usually, the small and large bowels are herniated, but, occasionally, the stomach, liver, gallbladder, spleen, uterus, adnexa, and urinary bladder may be herniated.
Signs of intestinal obstruction may be depicted; examples of these include multiple distended loops of bowel (both intraperitoneal and extraperitoneal), bowel loops greater than 17 mm in diameter, and increased peristalsis. Polyhydramnios may ensue in high intestinal obstructions. A bowel diameter of greater than 17 mm usually represents significant bowel dilation, and diameters greater than 11 mm are usually associated with a greater number of postnatal bowel complications.
A right paramedian paraumbilical abdominal wall defect is revealed, usually of 2-5 cm.Insertion of the umbilical cord is normal. Typically, no ascites is noted. Bowel perforation can cause calcification and an intramesenteric extra-abdominal pseudocyst
2.Omphalocele:
Pathophysiology: Various theories have been postulated; these include failure of the bowel to return into the abdomen by 10-12 weeks, failure of lateral mesodermal body folds to migrate centrally, and persistence of the body stalk beyond 12 weeks' gestation. Associated anomalies are common (45-88%).
Chromosomal anomalies (40-60%): These include trisomies 18,13, and 21
Cardiac defects (16-47%): These include ventricular and atrial septal defects, tetralogy of Fallot, pulmonary artery stenosis, coarctation of the aorta,
Genitourinary anomalies (40%): These include bladder extrophy and omphalocele, bladder extrophy, imperforate anus and spinal anomalies .
Neural tube and head and neck anomalies: These include neural tube defects, holoprosencephaly, encephalocele,
Gastrointestinal anomalies (40%): These include diaphragmatic hernia, malrotation, intestinal duplications, atresias, and ascites,
Musculoskeletal anomalies (10-30%): This includes scoliosis, hemivertebra, and camptomelic dwarfism,.
Maternal/fetal developmental abnormalities: These include oligohydramnios, polyhydramnios, intrauterine growth restriction (IUGR),
Beckwith-Wiedemann syndrome (5-10%)
Ultrasound findings :An omphalocele is diagnosed when a fetal anterior midline abdominal mass is demonstrated.
The mass consists of abdominal contents that have herniated through a midline central defect at the base of umbilical
cord insertion. The mean size of the defect is 2.5-5 cm. The mass has a smooth surface and contains abdominal viscera,
usually the liver and including the bowel and stomach. The membrane is not always visible. Wharton jelly may be
detectable as a hypoechoic lining between the layers of the covering of the membrane.
The umbilical cord attaches to the apex of the herniated mass.Fetal ascites is common and seen within the herniated
sac. Polyhydramnios, and occasionally oligohydramnios, may be present.
3.Prune Belly Syndrome:
The child with prune belly syndrome typically is male with a thin or lax abdominal wall and a long and dilated prostatic urethra from prostatic hypoplasia. A large, vertically oriented, thick-walled bladder; a urachal remnant from the dome of the bladder; and tortuous and dilated ureters. Varying amounts of hydronephrosis and varying degrees of renal dysplasia are seen. All have cryptorchidism.
Radiographic & ultrasonic findings:
Chest: Hypoplastic lungs, flared lower ribs secondary to the distended abdomen are seen.
Abdomen: Diffusely distended flanks are seen.
Kidneys: Sonography of the kidneys shows diffusely hyperechoic parenchyma, small parenchymal cysts, clubbed dysplastic calyces, and markedly tortuous ureters, which is sufficient to make the diagnosis. The increased echogenicity of the parenchyma is an indicator of underlying dysplasia of the renal tissue during early differentiation and maturation. The bladder is usually large and thick-walled.
Ureters: Ureters are markedly dilated and tortuous
Bladder: The bladder is vertical and trabeculated, with a urachal remnant at the dome.
Urethra: A wide and long posterior urethra is seen with a utricular remnant.
Cryptorchidism: The testes are in the abdomen or inguinal canals.
5-Neonate with Intestinal Obstruction
Etiology:
1. Duodenal Obstruction(atresia,stenosis,web)
2. Jejunal/ileal atresia.
3. Malrotation and mid gut volvulus.
4. Meconium Ileus.
5. Meconium Plug (Small left colon )
6. Hirschprung disease.
7. Anorectal malformation.
I-Hirschsprung Disease :
Pathophysiology: The congenital absence of ganglion cells in the distal alimentary tract is the pathologic sine qua non of HD. The aganglionosis present in HD results from a failure of cells derived from the neural crest to populate the embryonic colon during development. This failure results from a fundamental defect in the microenvironment of the bowel wall that prevents ingrowth of neuroblasts. So far, 8 genetic defects are known to be associated with HD, including mutations to the endothelin-B receptor gene and the RET proto-oncogene. Because of the polygenic nature of HD, the penetrance of the condition is variable; it leads to the variable manifestations of the disease.
Anatomy: HD is regarded as a neurocristopathy because it involves a premature arrest of the craniocaudal migration of vagal neural crest cells in the hindgut at weeks 5-12 of gestation to form the enteric nervous system. As a consequence, both intramural ganglion cells in the Meissner (submucosal) and Auerbach (myenteric) plexuses are absent. The anus is always involved, and a variable length of distal intestine may be involved as well. The aganglionic, aperistaltic bowel segment effectively prevents the propulsion of the fecal stream, resulting in dilation and hypertrophy of the normal proximal colon.
HD can be classified by the extension of the aganglionosis as follows:
• Classical HD (75% of cases): The aganglionic segment does not extend beyond the upper sigmoid.
• Long segment HD (20% of cases)
• Total colonic aganglionosis (3-12% of cases)
Some rare variants include the following:
• Total intestinal aganglionosis
• Ultra-short-segment HD (involving the distal rectum below the pelvic floor and the anus.
Clinical Details: Newborns with HD come to medical attention with the following symptoms:
• Failure to pass meconium within the first 48 hours of life
• Abdominal distension that is relieved by rectal stimulation or enemas
• Vomiting
• Neonatal enterocolitis
Symptoms in older children and adults include the following:
• Severe constipation
• Abdominal distension
• Bilious vomiting
• Failure to thrive
Children presenting with abdominal distension, explosive diarrhea, vomiting, fever, lethargy, rectal bleeding, or shock may possibly have HAEC. The risk for HAEC is greatest before HD is diagnosed or after the definitive pull-through operation. Also, children with Down syndrome have an increased risk for HAEC.
X-ray findings: Radiographs of the neonatal abdomen may show multiple loops of dilated small bowel with air-fluid levels that can usually be determined to be a distal bowel obstruction. An empty rectum is a common finding. A cutoff sign in the rectosigmoid region, with an absence of air distally, is a useful finding in HAEC.
HD is more definitively diagnosed by means of contrast enema examination, which can show the presence of a transition zone, irregular contractions, mucosal irregularity, delayed evacuation of contrast material, and other findings.
The transition zone is the term applied to the region in which a marked change in caliber occurs, with the dilated normal colon above and the narrowed aganglionic colon below. This sign is highly reliable of HD, but a failure to visualize this sign does not rule out HD.
The hallmark of the diagnosis is demonstration of the transition zone from the dilated bowel to the reduced-caliber bowel. Obviously, finding more than 1 sign increases the accuracy in diagnosis. Signs of HD after barium enema administration include the following:
• Transition zone (often subtle during first week of life)
• Abnormal, irregular contractions of aganglionic segment (rare)
• Thickening and nodularity of colonic mucosa proximal to transition zone (rare)
• Delayed evacuation of barium
• Mixed barium-stool pattern on delayed radiographs
• Distended bowel loops on plain radiographs that almost fill after contrast enema
• Question mark–shaped colon in total colonic aganglionosis
Ultrasonic Findings: Although sonography is not the first imaging tool for diagnosing HD, diagnosis is possible with real-time ultrasonography. Oestreich reported a case of unsuspected HD in a 1-month-old baby who went to the pediatrician for a check-up. A distended abdomen was noted. Sonography revealed the same pattern that is observed in the barium enema examination, that is, a dilated sigmoid narrowing to a narrow rectum.
Sonography may also help in determining the dynamic or adynamic state of fluid-filled or solid-filled bowel loops.
Hirschsprung disease. Frontal abdominal radiograph showing marked dilatation of the small bowel with no gas in the rectum.
Hirschsprung disease. Lateral view from a barium enema examination depicting the reduced diameter of the rectum and sigmoid.
Hirschsprung disease. A 24-hour-delayed radiograph obtained after a barium enema examination shows retention of barium and stool in the rectum. This is associated with a dilated stool-filled sigmoid.
II-Meconium Plug Syndrome:
Background: Meconium plug syndrome, also termed functional immaturity of the colon, is a transient disorder of the newborn colon characterized by delayed passage (>24-48 h) of meconium and intestinal dilatation. Contrast enema demonstrates the retained meconium as a filling defect or plug. that produces a double-contrast effect. Small left colon syndrome is a subset of meconium plug syndrome in which an enema demonstrates an apparent transition zone between the dilated and the normal-to-decreased caliber distal colon at the splenic flexure
Pathophysiology: Early descriptions of meconium plug syndrome emphasized the contrast-enema appearance and ascribed a possible etiologic role to the retained meconium, which is often dislodged after the enema study. Currently, meconium plug syndrome is understood as a transient functional disorder of the colon resulting from immaturity of the myenteric plexus nerve cells or their hormonal receptors. This distinguishes it from Hirschsprung disease, which may have identical clinical and radiographic findings in which nerve cells are absent in the distal diseased portion of the colon.
Anatomy: Anatomic changes in meconium plug syndrome vary. Usually, the colon is normal or may be mildly enlarged and filled with meconium. A change in the colon's diameter at the splenic flexure may be seen and is indistinguishable from that observed in Hirschsprung disease, although in the latter disorder the transition zone usually is in the rectosigmoid. In preterm infants weighing less than 1000 g, the entire colon may be small, producing an enema appearance similar to ileal atresia or meconium ileus.
Clinical Details: Clinically, the hallmarks of the disorder are abdominal distention and failure to pass significant meconium in the first 24 hours of life. Bilious vomiting may occur. Symptoms often are present before the first feeding, which helps distinguish the disorder clinically from necrotizing enterocolitis.
The incidence is increased in premature infants of diabetic mothers (especially the small left colon variant) and in infants whose mothers received magnesium sulfate for treatment of toxemia. Newborns with cystic
fibrosis also may present with meconium plug syndrome, although meconium ileus is more frequent and characteristic in these patients. Despite these associations, many patients have no apparent risk factor.
Radipgraphic Findings: Plain films usually demonstrate multiple dilated loops of bowel with absence of rectal gas. The presence or absence of air-fluid levels in the bowel is not helpful. Findings are similar to those of structural colonic or distal small bowel obstruction and help to exclude malrotation with volvulus or obstructing Ladd bands, in which the blockage usually occurs at the duodenum.
Contrast enema usually shows a moderately dilated colon filled with radiolucent material (the meconium plug). In the small left colon variant, a transition is seen from a relatively small to normal or increased caliber bowel in the region of the splenic flexure.
lateral view from contrast enema in a newborn demonstrates a normal-to-decreased caliber "empty" distal colon and dilated proximal bowel containing multiple plugs. The child responded clinically and
radiographically to a single enema
III-Necrotizing Enterocolitis :
Background: Necrotizing enterocolitis (NEC) is a serious gastrointestinal disease of unknown etiology in neonates. NEC is characterized by mucosal or transmucosal necrosis of part of the intestine. The very small, ill, infant who is born before term is most susceptible to NEC, and the incidence is increasing because of the improved survival rate in the high-risk group of infants born prematurely.
Pathophysiology: Several factors contribute to the development of neonatal NEC. The underlying pathology is the accumulation of gas in the submucosal layers of the bowel wall, which progresses to necrosis. Outcomes include eventual necrosis of the bowel loops; perforation; systemic sepsis; and, sometimes, death. The regions of bowel most often affected are the right side of the colon and the distal ileum, although any portion of the bowel is susceptible.
The major or most common contributor to NEC is sepsis; however, indwelling vascular catheters, assisted ventilation, respiratory acidosis, and hypoxemia all are contributing factors as well. NEC is primarily a complication of prematurity with possible hypoxemia, acidosis, hypotension, sepsis, and stress. The abnormality also occurs in ill full-term neonates, particularly those with a history of sepsis, hypoxia, asphyxia, or difficult resuscitation.
Polycythemia, the use of hypertonic formulas or medicines, and a too-rapid establishment of feeding may cause mucosal injury. Epidemics of NEC are documented, and identified infectious agents include Clostridium perfringens, Escherichia coli, Staphylococcus epidermidis, and rotavirus.
Clinical Details: Onset occurs 2 weeks to several months after birth. Meconium is usually passed normally, and the initial signs of NEC include abdominal distention and gastric retention of fluid. Manifestations of the disease develop after enteric feedings begin. Obviously bloody stool is observed in approximately 25% of patients. The onset of NEC can be insidious, and sepsis may occur before an intestinal abnormality is noted. The spectrum of presentations ranges from mild forms, with guaiac-positive stool, to severe forms, with peritonitis, bowel perforation, shock, and death. Progression may be rapid; progression of the disease after 72 hours is usual.
Pneumatosis is a late finding in NEC and usually indicates some necrosis of the bowel wall. The presence of irritability, distention, and bowel distention, especially when associated with bloody stool, is diagnostic of NEC.
Radiographic Findings: A high index of suspicion is essential in the diagnosis of NEC.
Abdominal radiographs may demonstrate multiple dilated loops of bowel that change little in their location and appearance with sequential studies. Pneumatosis intestinalis, or gas in the wall of bowel in a linear or bubbly pattern, is present in 50-75% of patients. Portal venous gas and gallbladder gas indicate serious disease. Pneumoperitoneum indicates a perforation. CT or water-soluble enema examination may be used to demonstrate pneumatosis or a site of perforation.
Radiograph demonstrates multiple dilated loops in the large bowel and small bowel. Note pneumatosis intestinalis with bubbly and linear gas collections in the bowel wall.
Anteroposterior image shows necrotizing enterocolitis with pneumatosis intestinalis.
Image shows free air secondary to bowel wall necrosis.
Portal venous air is present in a patient with pneumatosis intestinalis.
IV-Duodenal Atresia :
Background: Duodenal atresia represents complete obliteration of the duodenal lumen. The duodenal diaphragm or web is thought to represent a mild form of atresia. Duodenal stenosis (incomplete obstruction of the duodenal lumen) is discussed with duodenal atresia because they represent a spectrum of similar intrauterine events.
Annular pancreas occurs when pancreatic tissue surrounds the second portion of the duodenum. If the encirclement is complete, it may be associated with complete or incomplete duodenal obstruction. Since duodenal atresia or stenosis occurs in all cases of annular pancreas, consider the anomalous pancreas a secondary change rather than a primary cause of duodenal obstruction.
Pathophysiology: The etiology of duodenal atresia and stenosis is unknown. Failure of recanalization of the duodenal lumen remains the favored theory compared with intrauterine vascular ischemia.
During the third week of embryonic development, the second portion of the duodenum at the junction of the foregut and midgut forms biliary and pancreatic buds derived of endoderm. During the next 4 weeks, these buds differentiate into the hepatobiliary system, with the development and subsequent fusion of the 2 pancreatic anlagen. Concurrently, the epithelium of the duodenum undergoes active proliferation, which, at times, completely obliterates the duodenal lumen. Vacuolization, followed by recanalization, reestablishes the hollow viscus.
The second part of the duodenum is the last to recanalize. The early-forming biliary system consists of 2 channels arising from the embryonic duodenum. This structure creates a narrow segment of bowel, approximately 0.125 mm in length, that is interposed between the 2 biliary channels. This narrow region is the area most prone to problems, with recanalization and atresia formation. The ampulla of Vater usually is immediately adjacent to or traverses the medial wall of the diaphragm. The presence of a bifid biliary system, or the insertion of one duct above and one duct below the atresia, is rare and occurs when both biliary duct anlagen remain patent. The presence of bile above and below the atresia indicates a bifid biliary system.
Clinical Details: Bile-stained vomitus in neonates aged 24 hours or younger is the typical presentation of atresia or severe stenosis. Minimal duodenal obstruction in mild stenosis or membrane may have few symptoms. In a few cases, the atresia is proximal to the ampulla of Vater and the vomitus is free of bile.
Both duodenal anomalies can be associated with other GI and biliary tract abnormalities (malrotation, esophageal atresia, ectopic anus, annular pancreas, gallbladder or biliary atresia, vertebral anomalies). In addition, duodenal atresia can be associated with a duodenal diaphragm as well as congenital abnormalities in other systems. Examples include vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, and radial and renal anomalies (VATER) association and vertebral, anal, cardiac, tracheal, esophageal, renal, and limb (VACTERL) association. Anomalies of the kidneys can occur in VATER association. These are usually aplasia, dysplasia, hydronephrosis, ectopia, persistent urachus, vesicoureteral reflux, ureteropelvic obstruction, and other conditions.
Radiographic Findings: The double-bubble sign represents dilatation of the stomach and duodenum. This configuration most commonly occurs with duodenal atresia and an annular pancreas. An annular pancreas is almost always associated with duodenal atresia.
In a few cases of duodenal atresia, air can be observed distal to the area of obstruction. The anomalous hepatopancreatic ducts permit movement of air through a Y-shaped ductal system, with one limb proximal to the obstruction and one limb distal to the atresia.
When duodenal atresia is combined with esophageal atresia, no air is observed in the stomach, and because the stomach is obstructed at both ends, the infant presents with a large, opaque upper midabdominal mass. If esophageal atresia is present with a distal fistula, air is present in the stomach and duodenum.
Duodenal obstruction in the neonate may be partial or complete and secondary to intrinsic or extrinsic abnormalities. The duodenal bulb may be larger in duodenal atresia than in obstructions of the duodenum. Increased intramural pressure in duodenal obstruction can result in gastric pneumatosis.
Anteroposterior radiograph of abdomen depicts the double-bubble sign in duodenal atresia.
6-Patient with Jaundice Etiology:
1. Biliary atresia.
2. Caroli disease.
3. Choledochal cyst.
4. Cholecdochocele.
5. Cholelithiasis.
6. Diffuse hepatic parenchymal disease :Hepatitis-Fatty infiltration-Cirrhosis.
7. Hepatic Masses.
8. Hepatic veno-occlusive disease.
I-Caroli Disease :
Background: Caroli disease is a nonobstructive dilatation of the intrahepatic bile ducts. This is a rare congenital disorder that classically causes saccular ductal dilatation, which usually is segmental. Caroli disease is associated with recurrent bacterial cholangitis and stone formation.
Caroli disease also is known as communicating cavernous ectasia or congenital cystic dilatation of the intrahepatic biliary tree. It is distinct from other diseases that cause ductal dilatation caused by obstruction. It is not one of the many choledochal cyst derivatives.
Pathophysiology: Caroli disease involves congenital cystic dilatation of the intrahepatic biliary radicles of the liver. It is believed to have an autosomal-recessive inheritance pattern. It may be associated with autosomal-recessive polycystic kidney disease. The likely mechanism involves an in utero event that arrests ductal plate remodeling at the level of the larger intrahepatic bile ducts. Insufficient resorption of the ductal
plates leads to the formation of multiple primitive bile ducts surrounding the central portal vein. These enlarge, dilate, and become ectatic. This effect may be segmental.
Two forms of Caroli disease exist: a simple or classic type and a second type that is associated with congenital hepatic fibrosis.
Drawing shows the main right hepatic duct and the multiple segmental branch dilatations related to Caroli disease. Note the saccular dilatations that can occur, involving the right lobe of liver in this case.
Clinical Details:
Dr J Caroli of France first described this hereditary (congenital) disease in 1958.
Signs and symptoms
Patients may have bilirubinemia and abdominal pain. They generally are febrile. Other complaints, such as nausea and vomiting, may be nonspecific. Liver function test results may be abnormal and include elevated alkaline phosphatase levels. On examination, patients may have hepatomegaly, especially if they have hepatic fibrosis. Portal hypertension related to this may cause variceal bleeding. Elevation in white blood cell counts and positive blood culture results suggest sepsis and cholangitis. Patients may have long symptom-free periods. Malignancy occurs in approximately 7% of patients.
Other etiologies for these symptoms should be excluded. The differential diagnosis can include sclerosing cholangitis, oriental cholangitis, choledochal cyst, and hydatid disease.
Complications
The complications of Caroli disease, especially recurrent bouts of cholangitis, may be present first. Intrahepatic calculi and abscesses are common. Stone passage can cause pancreatitis.
CT Findings: Dilated segmental intrahepatic biliary radicles are present without involvement of the extrahepatic biliary tree. Preinfused scans may show hyper-attenuating sludge and stones or debris.
Hypo-attenuating, tubular branching structures are identified; these communicate and extend from the porta hepatis toward the periphery. CT scan with IV contrast enhancement can show tiny dots, representing intraluminal portal veins, within the dilated intrahepatic bile ducts. This is termed the central dot sign. Take 3D images with or without the CT cholangiographic technique to help prove the relationship of the dilated structure to the ductal system, although this is better accomplished with MRCP (see below). CT can help depict abscesses and guide percutaneous drainage.
CT
Complications such as cholangitis, choledocholithiasis, or cholangiocarcinoma may be present and can be identified with CT imaging. Portal hypertension can be present and result in hepatosplenomegaly with varices. Contrast-enhanced images obtained through the kidneys can show associated multiple renal cysts.
MRI Findings: Dilated segmental intrahepatic biliary radicles can be identified with MRI, as with CT and ultrasonography. MRCP reveals similar findings and allows better review of the results, especially with a computer workstation. This noninvasive 3D technique is a good alternative to ERCP or direct cholangiography. This can confidently show the communication of the multiple cysts, which is mandatory for the differential diagnosis with cystic disease of the liver and multiple abscesses. Complications of Caroli disease also can be identified with MRI.
Ultrasonic Findings: Ultrasonography is very helpful. It is the examination of choice. Dilated segmental intrahepatic biliary radicles are easily detected. No obstruction is present. The cystlike tubular anechoic spaces converge toward the porta hepatis. They are largest in the superior part of the liver. The intraluminal portal vein sign is related to the protrusion of the portal vein branches into the cyst wall. Color flow Doppler ultrasonography is helpful in showing blood flow in these branches but no flow is present in the bile-containing spaces. Portal branches bridge the cyst walls.
Ultrasonography can also help in the diagnosis of complications and in the follow-up of patients with Caroli disease. Intraductal calculi are echogenic with acoustic shadowing.
Ultrasonography-guided needle aspiration of bile from the cystlike lesions may be beneficial in the diagnosis of cholangitis and in confirming that the cysts communicate with the biliary tree. Congenital hepatic fibrosis is associated with Caroli disease and may be diagnosed with sonograms that show abnormal liver echogenicity. Ultrasonography-guided core biopsy may be performed, if necessary, to obtain liver samples for histologic evaluation to confirm this condition. In addition, polycystic renal disease, which is associated with Caroli disease, can be confirmed with sonography.
Degree of Confidence: This is an excellent tool. A positive result has good predictive value and permits diagnosis with a high level of confidence. Caroli disease is the only condition in which dilated ducts surround the portal radicles; this finding at ultrasonography may obviate other invasive diagnostic techniques.
Isoyopic Findings: Hepatobiliary scintigraphy with technetium 99m iminodiacetic acid (99mTc
IDA) agents reveals large, irregular, multifocal collections of the radiotracer in the liver. A beaded appearance in the dilated ducts, if present, is somewhat pathognomonic. These collections correspond to the segmental dilatations, and no extrahepatic obstruction is present, although bile stasis and stone formation may result in atypical obstruction.
On early images, if the ducts are dilated enough, they appear as photopenic branching areas within the liver. Single photon emission computed tomography (SPECT) may better outline the ductal pattern but it is most helpful in the evaluation of focal disease.
II-Choledochal Cyst :
Background: Choledochal cysts are congenital anomalies of the bile ducts. They consist of cystic dilatations of the extrahepatic biliary tree, intrahepatic biliary radicles, or both. The first anatomic study of a choledochal cyst in the Western literature was published by Vater and Ezler in 1723. Douglas is credited with the first clinical report in a 17-year-old girl who presented with intermittent abdominal pain, jaundice, fever, and a palpable abdominal mass.
Alonso-Lej et al provided the first systematic description of choledochal cysts in 1959 based on the clinical and anatomic findings in 96 cases. The resultant system classified choledochal cysts into 3 types and outlined therapeutic strategies for each. The classification system for choledochal cysts was further refined by Todani et al and currently includes 5 major types (Todani, 1977).
Pathophysiology: The pathogenesis of choledochal cysts is most likely multifactorial. Some aspects of the disease are consistent with a congenital etiology, others with a congenital predisposition to acquiring the disease under the right conditions.
The vast majority of patients with choledochal cysts have an anomalous junction of the common bile duct with the pancreatic duct (anomalous pancreatobiliary junction [APBJ]). An APBJ is characterized when the pancreatic duct enters the common bile duct 1 cm or more proximal to where the common bile duct reaches the ampulla of Vater.
Anatomy: The following discussion of the pertinent anatomy of choledochal cysts is based on the Todani classification published in 1977.
• Type I choledochal cysts are most common and represent 80-90% of the lesions. Type I cysts are dilatations of the entire common hepatic and common bile ducts or segments of each. They can be saccular or fusiform in configuration. Type I cysts can be divided into 3 subclassifications, including type IA cysts, which are typically saccular and involve the entire extrahepatic bile duct (common hepatic duct plus common bile duct) or the major portion of the duct.
• Type II choledochal cysts are relatively isolated protrusions or diverticula that project from the common bile duct wall. They may be sessile or may be connected to the common bile duct by a narrow stalk.
• Type III choledochal cysts are found in the intraduodenal portion of the common bile duct. Another term used for these cysts is choledochocele.
• Type IVA cysts are characterized by multiple dilatations of the intrahepatic and extrahepatic biliary tree. Most frequently, a large solitary cyst of the extrahepatic duct is accompanied by multiple cysts of the intrahepatic ducts. Type IVB choledochal cysts consist of multiple dilatations that involve only the extrahepatic bile duct.
• Type V choledochal cysts are defined by dilatation of the intrahepatic biliary radicles. Often, numerous cysts are present with interposed strictures that predispose the patient to intrahepatic stone formation, obstruction, and cholangitis. The cysts are typically found in both hepatic lobes. Occasionally, unilobar disease is found and most frequently involves the left lobe.
Clinical Details: Some patients do not present until adulthood. In many adult patients, subclinical bile duct inflammation and biliary stasis have been ongoing for years. Adults with choledochal cysts can present with hepatic abscesses, cirrhosis, recurrent pancreatitis, cholelithiasis, and portal hypertension.
The clinical history and presentation of a patient with a choledochal cyst varies with the patient's age. Overt dramatic signs and symptoms are more common in infancy, whereas manifestations are more subtle and protean in adulthood.
Infants frequently come to clinical attention with jaundice and the passage of acholic stools. If this presentation occurs in early infancy, a workup to exclude biliary atresia may be initiated. Infants with choledochal cysts can have a palpable mass in the right upper abdominal quadrant; this may be accompanied by hepatomegaly.
Children in whom the condition is diagnosed after infancy present with a different clinical constellation, which includes intermittent bouts of biliary obstructive symptoms or recurrent episodes of acute pancreatitis. Children in whom biliary obstruction is present may also have jaundice and a palpable mass in the right upper quadrant. The correct diagnosis is occasionally more difficult in children with pancreatitis. Often, the only clinical symptoms are intermittent attacks of colicky abdominal pain. Eventually, an analysis of biochemical laboratory values reveals elevations in amylase and lipase levels. This leads to the proper diagnostic imaging workup.
Adults with choledochal cysts frequently complain of vague epigastric or right upper quadrant abdominal pain. Indeed, the most common symptom in adults is abdominal pain. A classic clinical triad of abdominal pain, jaundice, and a palpable right upper quadrant abdominal mass has been described in adults with choledochal cysts, although this is found in only 10-20% of patients. Cholangitis can be part of the clinical presentation in adult patients with biliary obstruction.
Choledochal cysts not appearing until adulthood can be associated with a number of serious complications resulting from long-standing biliary obstruction and recurrent bouts of cholangitis. These include cholelithiasis, severe pancreatitis, hepatic abscesses, hepatic cirrhosis, and portal hypertension.
CT Findings: Abdominal CT scanning is useful in the diagnostic algorithm for choledochal cysts. CT is highly accurate and offers a great deal of information that is helpful not only in confirming the diagnosis but also in planning surgical approaches.
CT scans of a choledochal cyst demonstrate a dilatated cystic mass with clearly defined walls, which is separate from the gallbladder. The fact that this mass arises from or actually is the extrahepatic bile duct usually is clear from its location and its relationships to surrounding structures. The cyst is typically filled with bile, which produces water-like attenuation. Depending on the patient's age and clinical history, the wall of the cyst can appear thickened, especially if multiple episodes of inflammation and cholangitis have occurred.
Most patients with choledochal cysts have undergone abdominal US imaging prior to CT scanning. US findings suggest the diagnosis in most patients and may be conclusive in many. According to Lipsett and colleagues, CT scanning confirms the diagnosis if it is unclear and provides information concerning the relationships of the cyst to surrounding structures including the portal vein, duodenum, and liver. In addition, CT scanning is superior to US in defining the extent of the cyst in the extrahepatic biliary system and in detecting intrahepatic disease.
Recently, CT cholangiography has been used in the diagnosis of choledochal cysts. Spinzi and colleagues published a case report describing CT cholangiography in the diagnosis of a type I choledochal cyst in an adult. The cyst and its extent were demonstrated clearly. The authors did note the need to use retrograde biliary contrast enhancement or intravenous contrast enhancement, and they stated that MR cholangiography may one day obviate CT cholangiography.
Large type I choledochal cyst and adjacent gallbladder.
MRI Findings: Use of MRI and MRCP techniques is increasing dramatically for the noninvasive diagnosis of biliary and pancreatic diseases. Choledochal cysts are no exception. These cysts appear as large fusiform or saccular masses that may be extrahepatic, intrahepatic, or both, depending on the type of cyst. They produce a particularly strong signal on T2-weighted images. Associated anomalies of the pancreatic duct, its junction with the common bile duct, and the long common channel formed by the 2 are usually well demonstrated on MRI/MRCP images.
Ultrasonic Findings: US is the initial screening examination of choice in patients with choledochal cysts. Pertinent findings include a cystic extrahepatic mass. Depending on the skill of the operator, the specific type or class of choledochal cyst may be identified. Newer high-resolution US machines help clinicians make such diagnoses. Furthermore, advances in US technology have enabled ultrasonographers to make the diagnosis in the antenatal period.
US findings are diagnostic in many patients; however, in the preoperative period, complementary studies, such as ERCP, CT, or MRI/MRCP, may be helpful in delineating details of the surrounding anatomy, the location of an APBJ, and the length of the common pancreatobiliary channel.
Abdominal US findings can help in detecting associated conditions and complications of choledochal cysts, such as choledocholithiasis, intrahepatic biliary dilatation, portal vein thrombosis, gallbladder or biliary neoplasms, pancreatitis, and hepatic abscesses.
The importance of abdominal US in this disease process cannot be understated. This is highlighted by the fact that US findings initially suggested the diagnosis in many of the studies dealing with other diagnostic modalities referenced in this article.
Diagnostic sonogram demonstrating a type I choledochal cyst in a 4-month-old child presenting with elevated hyperbilirubinemia and hepatic transaminase levels.
Isotopic Findings: Hepatobiliary scintigraphic modalities are used commonly in the setting of acute cholecystitis and in the investigation of neonatal jaundice. In addition, these techniques are useful in the diagnosis of choledochal cysts.
Kao and co-investigators studied the significance of nonvisualization of the gallbladder on cholescintigraphy in 27 patients with choledochal cysts. Nonvisualization of the gallbladder occurred in 18 (67%) of 27 patients at 4 hours after injection of the radionuclide. Most of the patients did not have acute cholecystitis. The authors concluded that nonvisualization of the gallbladder in this patient population is not necessarily indicative of acute cholecystitis and that large choledochal cysts may compress the gallbladder, leading to nonvisualization.
Surgical specimen
7-Patient with Abdominal Pain
Etiology :
1. Appendicitis.
2. Pancreatitis.
3. Crhon’s disease
4. Colitis :Ulcerative/Pseudomembranous/Neutropenic.
5. Meckel’s diverticulitis.
6. Cholecystitis.
7. Ovarian cyst complications (torsion/rupture/infection)
8. Urinary causes (stones/pyelonephritis)
9. Intussusception.
10. Volvulus (gastric-mid gut volvulus-caecal-sigmoid )
11. hematocolpos
12. Sickle cell crisis (splenic /bowel infarction)
13. Referred from pneumonia
US show dilated lind ended bowel loop segment :Appendicitis
8-Hypertensive Child
Etiology :
1. Renal Cortex scarring (36%).
2. Glomerulonephritis (23%)
3. Co-arctation of Aorta (10% )
4. Fibromuscular dysplasia of renal arteries (10%)
5. Phaeochromocytoma-functioning neuroblastoma (3%)
6. Polycystic renal disease (6%)
7. Hemolytic Uremic syndrome (4%)
8. Renal tumors (2%)
9. Essential (3%).
MCUG :Bilteral Grade 5 reflux with right duplex kidney
9-Child with scrotal Problems
A-Scrotal Pain
Etiology :
1. Epididymo-orchitis.
2. Testicular torsion.
3. Testicular abscess.
4. Varicoceke.
5. Complicated Hernia.
6. Hematoma.
B-Scrotal Masses
Etiology :
1. Neoplastic :
• Primary :a) Germ Cell tumor (70-90%)..Yolk sac tumor-teratoma. b)Sex cord stromal tumors (10-30%)
• Secondary :Leukemia-lymphoma- Wilm's tumor. 2. Non neoplastic :
3. Hydrocele.
4. Spermatocele.
5. Epididymal cyst.
III-CNS and Head &Neck
1.Patient with a neck mass
Etiology :
1. Branchial cleft cyst.
2. Thyroglossal cyst.
3. Thyroid masses.
4. Lymphadenopthies.
5. Retropharyngeal abscess .
6. Fibromatosis Coli.
7. Dermoid and dermoid cysts.
8. Rhabdomyosarcoma.
9. 11 .Salivary gland origin (cysts-masses )
2.Patient with abnormal skin findings
Etiology :
1. Neurofibromatosis.
2. Tuberous Sclerosis.
3. Sturge Weber Syndrome.
4. Von-Hipplel Lindau syndrome.
5. Ataxia Telangiectasia.
6. Gorlin Syndrome.
7. Cowden syndrome.
8. Klippel –Trenauny syndrome.
9. Wyburn-Mason syndrome.
Sturge Weber syndrome :Small left cerebral hemisphere ,gyral calcifications.
3-Patient with Proptosis
Etiology :
A-Extraconal lesions :
Dermoid cyst.
Rhabdomyosarcoma.
Dacryocystocele.
Orbital Abscess.
B-Intraconal Lesions:
Orbital Pseudotumor.
Hemangioma.
Optic nerve glioma.
Meningioma.
Tolosa Hunt Syndrome.
Retinoblastoma.
Right intraconal mass -Rhabdomyosarcoma
CT:Persitent Hyperplastic primary vitreous
Right orbital haemangioma
4-Patient with Epilepsy
Etiology:
1. Perinatal accident (40%)
2. Congenital anomalies and phakomatosis (40%)
3. Post Hypoxic Ischemic Encephalopathy (10% )
4. Cerebral trauma (10% )
5. Cerebral tumors (1 % )
Causes of epilepsy according to age :
Age Causes
Neonate Anoxia- Neural malformation- Post infectious.
Infant Anoxia-malformation-post infectious –Sturge Weber Syndrome-Tuberous sclerosis-Aicardi syndrome-Mitochondrial diseases.
Children Ischemia –infection-trauma
Newly discovered epilepsy
Tumor –Vascular malformations (AVM-Cavernoma)-Neural malformation (Cortical dysplasia- Hippocampal sclerosis)-Hypothalamic hamartoma.
Specific diagnosis :
1.Holoprosencephaly:
Holoprosencephaly denotes an incomplete or absent division of the embryonic forebrain (prosencephalon) into distinct lateral cerebral hemispheres.
De Myer categorized holoprosencephaly into 3 types (from most severe to least severe): (1) alobar holoprosencephaly, or complete absence of midline forebrain division resulting in a monoventricle and fused cerebral hemispheres; (2) semilobar holoprosencephaly, or incomplete forebrain division resulting in partial separation of cerebral hemispheres, typically posteriorly; and (3) lobar holoprosencephaly, or complete ventricular separation with focal areas of incomplete cortical division or anterior falcine hypoplasia.
2.Schizencephaly :
Schizencephaly is an uncommon disorder of neuronal migrational characterized by a cerebrospinal fluid–filled cleft, which is lined by gray matter. The cleft extends across the entire cerebral hemisphere, from the ventricular surface (ependyma) to the periphery (pial surface) of the brain.
The clefts may be unilateral or bilateral and may be closed (fused lips), as in schizencephaly type I, or separated (open lips), as in schizencephaly type II.
Open lip Schizencephaly
3.Heterotopia:
Gray-matter heterotopia means collections of gray matter in abnormal locations.
It can be nodular or laminar.
Heteropic gray matter
5-Patient in STROKE
Etiology:
1. Hypoxic Ischemic encephalopathy.
2. Venous thrombosis ..(extension of infection)
3. Moya Moya disease .
4. Vein of Galen Malformation.
5. Arteriovenous malformations.
6. Cavernous hemangioma.
Cerebral aneurysms.
Hypoxic Ischemic Encephalopathy :
In spite of major advances in monitoring technology and knowledge of fetal and neonatal pathologies, perinatal
asphyxia or, more appropriately, hypoxic-ischemic encephalopathy (HIE), remains a serious condition, causing
significant mortality and long-term morbidity.
Brain hypoxia and ischemia due to systemic hypoxemia, reduced cerebral blood flow (CBF), or both are the primary
physiological processes that trigger HIE. The initial compensatory adjustment to an asphyxial event is an increase in
the CBF due to hypoxia and hypercapnia. In adults, CBF is maintained at a constant level despite a wide range in
systemic BP. This phenomenon is known as the cerebral autoregulation, which helps to maintain the cerebral perfusion.
Limited data on the preterm infant suggests that a range of blood pressures exist over which cerebral blood flow is
stable.
Some experts have postulated that in the healthy term newborn the BP range at which the CBF autoregulation is
maintained is quite narrow (perhaps between 10-20 mm Hg, compared to the 40 mm Hg range in adults noted above).
In the fetus and newborn suffering from acute asphyxia, after the early compensatory adjustments fail, the CBF can
become pressure-passive, at which time brain perfusion is dependent on systemic BP. As BP falls, CBF falls below
critical levels, and the brain continues to suffer from diminished blood supply and a lack of sufficient oxygen to meet
its needs. This leads to intracellular energy failure. During the early phases of brain injury, brain temperature drops, and
local release of the neurotransmitter, such as g-aminobutyric acid transaminase (GABA), increase. These changes
reduce cerebral oxygen demand, transiently minimizing the impact of asphyxia.
At the cellular level, neuronal injury in HIE is an evolving process. The magnitude of the final neuronal damage
depends on both the severity of the initial insult and the damage due to reperfusion injury and apoptosis . The extent,
nature, severity, and the duration of the primary injury are all important in affecting the magnitude of the residual
neurological damage.
Following the initial phase of energy failure from the asphyxial injury, cerebral metabolism may recover, only to
deteriorate in the secondary phase, or reperfusion. This new phase of neuronal damage, starting at about 6-24 hours
after the initial injury, is characterized by cerebral edema and apoptosis. This phase has been called the "delayed phase
of neuronal injury." Additional factors that influence outcome include the nutritional status of the brain, severe intrauterine growth
restriction, preexisting brain pathology or developmental defects of the brain, and the frequency and severity of
seizure disorder that manifests at an early postnatal age (within hours of birth).
At the biochemical level, a large cascade of events follow HIE injury. Both hypoxia and ischemia increase the release
of excitatory amino acids (EAAs), such as glutamate and aspartate, in the cerebral cortex and basal ganglia. EAAs
cause neuronal death through the activation of receptor subtypes such as kainate, N-methyl-D-aspartate (NMDA), and
amino-3-hydroxy-5-methyl-4 isoxazole propionate (AMPA). Activation of receptors with associated opening of ion
channels (eg, NMDA) lead to increased intracellular and subcellular calcium concentration and cell death.
A second important mechanism for the destruction of ion pumps is the lipid peroxidation of cell membranes, in which
enzyme systems, such as the Na+/K+-ATPase, reside; this can cause cerebral edema and neuronal death. EAAs also
increase the local release of nitric oxide (NO), which may exacerbate neuronal damage.
The EAAs may also disrupt the factors that control apoptosis, increasing the pace and extent of programmed cell death.
The regional differences in severity of injury may be explained by the fact that EAAs particularly affect the CA1
regions of the hippocampus, the developing oligodendroglia, and the subplate neurons along the borders of the
periventricular region in the developing brain. This may be the basis for the disruption of long-term learning and
memory faculties in infants with HIE.
Role of Imaging :
o A CT scan of the head can be especially useful to confirm cerebral edema (obliteration of cerebral ventricles,
blurring of sulci) manifested as narrowness of the lateral ventricles and flattening of gyri. Areas of reduced density
that indicate evolving zones of infarction may be present. Evidence of hemorrhage in the ventricles or in the cerebral
parenchyma may also be seen..
An early diagnosis may help in obtaining early neurosurgical consultation and, possibly, surgical therapy.
MRI is valuable in moderately severe and severe HIE, particularly to note the status of myelination, to note white-gray
tissue injury, and to identify preexisting developmental defects of the brain. Diffusion-weighted MRI scans are also
useful early in the course of treatment to identify those areas of the brain with edema.
However the easy access to CT ,and its more accurate demonstration of bleeding put itself in a prominent position in
evaluation of HIE .
CT depicts focal, multifocal, and generalized ischemic lesions. In the first few days after a severe hypoxic-ischemic
insult, bilateral hypoattenuations are seen and probably reflect both neuronal injury and edema. CT neuropathologic
studies show that areas of edema are correlated with hypoattenuation lesions when autopsy is performed within 10 days
of CT, but generalized edema may obscure focal ischemic lesions. Diffuse cortical injury is not initially detected on
CT. After days to weeks, diffuse hypoattenuation may appear, with loss of the gray matter–white matter differentiation.
Diffuse cerebral atrophy with ex vacuo ventricular dilatation due to severe hypoxemic insult may take several weeks to
develop. Atrophy is a consequence of cortical and white-matter destruction.
CT scanning can be performed to help reliably diagnose generalized edema in the premature newborn.
In partial asphyxia ,there is relative preservation of blood flow to the basal ganglia and brain stem ,the “watershed
zones “ between the major arterial territories being most affected .
After 48 hours, CT may depict focal ischemic infarcts well. On the first day after a focal thromboembolic event, the
ischemic area may not be visible on CT. A CT scan depicting hypoattenuation in the distribution of the left middle
cerebral artery in the first day of life suggests prenatal-onset of ischemia. Symptoms of a focal infarct (usually seizures)
on the first day of life with normal CT findings and with hypoattenuation developing over the first week suggest
perinatal-onset ischemia. Hemorrhagic conversion of a focal ischemic lesion is uncommon in the neonatal period, but
CT can depict it easily.
Rt occipital infarction
A CT scan demonstrating generalized, diffuse hypoattenuation after a hypoxic-ischemic event is predictive of
both neonatal death and long-term severe disability, whereas normal CT findings are predictive of mild
disability or a normal outcome. Regions of high metabolic activity are at risk during profound asphyxia.Sites of active myelination ,such as the
posterior limbs o internal capsule and perirolandic regions are particularly vulnerable .
Severe cerebral edema may produce the so-called reversal sign The cerebral white matter has greater Ct density than
the gray matter.
This reversal of density is felt due to accumulation of blood in the capillaries and veins of the white matter because of
increased intracranial and venous pressure.
Status marmoratus is a rare manifestation of profound HIE ,that occurs in term infants.
Hyprermyelination,neuronal loss ,and gliosis occur in the thalami and basal ganglia .There may be hypodensity seen
acutely on CT due to edema and necrosis .
Hyperdensity may then develop due to hemorrhage or mineralization in these anantomic regions .
In somecases ,due to relative preservation of perfusion of the posterior fossa and brain stem ,these structures appear
dense when compared with the rest of the brain producing the so-called White cerebellum sign .
Status marmoratus .
Reversal sign indicates an extremely poor prognosis ;profound atrophy frequently follows this severe asphyxic injury
and there may be cystic or cavitary changes ,mineralization ,and gliosis .
CT may depict hemorrhagic lesions, which are seen in 10-25% of patients with HIE .. These lesions include
intraparenchymal, intraventricular, and subarachnoid hemorrhages.
Occlusive disease may affect one or more specific vascular distribution. Emboli are flow directed and principally
occlude vessels in the middle cerebral artery territory
In vascular thrombosis the vessel may be hyperattenuating due to clotted blood . CT may also depict the delta sign
(clot in the sinus) or the empty delta sign (partially recanalized clot in the sinus).
On CT, PVL can be visualized around the frontal horns or posteriorly around the trigonal area of the lateral ventricles.
PVL appears as a region of decreased attenuation, occasionally intermixed with areas of increased attenuation due to
secondary hemorrhage. Periventricular hypoattenuations should be interpreted carefully because maturation and
myelination processes increase the lipid and protein content but the water content of the white matter. These changes
explain the findings of hypoattenuations in neonates with normal development.
6-Patient with Deafness
Etiology :
A-Congenital causes:
1. External auditory canal atresia.
2. Middle ear cavity hypoplasia.
3. Absence, rotation ,fusion or dysplasia of ossicles.
4. Treacher Collins dysplasia.
5. Inner ear anomalies :
6. Malformation of lateral semicircular canal .
7. Michel deformity =complete labyrinthine aplasia.
8. Large common cavity (vestibule &cochlea).
9. Cochlear aplasia/hypoplasia.
10. Mondini Malformatiom(less than 21/2 turn of cochlea.-most common)
11. 6.Internal auditory canal atresia and stenosis.
12. 7.Vestibular aqueduct dilatation or obliteration.
B-Inflammatory lesions:
1. Otitis media and mastoiditis.
2. Otitis externa.
C-Neoplastic lesions:
1. Congenital Cholesteatoma.
2. Fibrous dysplasia.
3. Bony exostosis.
4. Nerve shealth tumors.
5. Glomus tumors.
6. Metastasis.
7. Rhabdomyosarcoma.
8. Langerhans cell histiocytosis.
D-Traumatic lesions:
E-Vascular causes:
Aberrant course of ICA.
High jugular bulb position.
7-Child with neurological signs of a spinal cord lesion.
Etiology :
1. Extradural causes.
2. Intradural/extramedullary causes.
3. Intramedullary causes.
8-Neonate with spinal dysraphism Pathophysiology: The defect of spinal dysraphism occurs in the first 8.5 weeks of fetal life. The neural tube develops
from ectodermal cells, while mesoderm forms the bony elements, meninges, and muscle. The skin is separated from the
neural tube by the mesoderm. Incomplete separation of ectoderm from the neural tube results in cord tethering,
diastematomyelia, or a dermal sinus. Premature separation of the cutaneous ectoderm from the neural tube results in
incorporation of mesenchymal elements between the neural tube and skin, which may result in the development of
lipomas. If the neural tube fails to fuse in the midline posterior spinal abnormalities such as myelomeningoceles occur.
Types :
=====
1. Spina bifida Aperta (open)
Myeloschisis.
Cranioschisis.
Dorsal meningocele.
Myelomeningocele.
Myelocele.
Chiari II malformation.
2. Spina bifida occulta ( occult)
Lipomyelomeningocele.
Lipoma.
Congenital dermal sinus.
Tethered cord .
Myelocystocele.
Meningocele.
Split notochord syndrome.
3. Associations .
Hydromelia.
Hemimyelocele.
Developmental tumor
Role of imaging:
MRI findings:
MRI findings include absent posterior bony elements at the site of the defect. The soft tissue sac containing CSF may
be obvious, and the conus is invariably low, coursing dorsally within a capacious dural sac.
Inclusion dermal tissue is generally evident as a rounded mass with variable signal intensity often greater than that of the surrounding CSF.
Arnold-Chiari II malformations are noted in nearly all cases of myelomeningocele.
The small posterior fossa, low insertion of the tentorium, and downward displacement of cerebellar tissue and medulla through a widened foramen magnum are obvious. When the medullary migration is not vertical, the characteristic cervicomedullary kink is noted.
Syringomyelia of the cervical cord or syringobulbia and progressive dilatation of the fourth ventricle may account for worsening neurological deficit. Additional findings in Chiari II malformation include partial agenesis of corpus callosum, large massa intermedia, and a beaked tectum. Rarely, a Chiari I malformation is associated with myelomeningoceles in which only the tonsils herniate below the foramen magnum.
A tethered cord manifests itself as a low conus and associated spinal lesions. By the age of 2 months, a conus below L2-L3 is considered abnormal. Axial T1-weighted images are most accurate in determining the conus level.A low cord invariably occurs with a myelomeningocele and retethering may occur after repair.
Posterior neural arch defects and an increase interpedicular distance are often associated with a lumbosacral lipoma. T1-weighted images have high sensitivity in the detection of lipomas because of the short relaxation time of fat. The fat content may also be confirmed by using fat-saturation techniques.
The diagnosis of a thickened filum is made when the filum measures more than 2 mm at the L5-S1 disk space.
In diastematomyelia, MRI is used to evaluate the extent of cord clefting, a low position of the conus, scoliosis, other bony anomalies, and the commonly associated syringohydromyelia. The bony spur is well seen on T1-weighted MRIs when fatty marrow is present.
Dermoids and epidermoids may be associated with a dermal sinus or occur in isolation. When not associated with dermal sinuses, they may occur with progressive compressive myelopathy or acute onset chemical meningitis due to the rupture of the cyst and the spread of cholesterol crystals in the CSF. The thoracic lumbar and sacral spine are affected, with a slight increase in incidence in the craniocaudal direction.
Lipomas are hyperintense on T1-weighted MRIs. Spinal lipomas are usually found in the extradural space in the thoracic region.
T1- and T2-weighted sagittal MRIs of the lumbar spine show an extradural spinal lipoma communicating with the subcutaneous fat.
9-Abnormal skull shape
Craniosynostosis:
Background: Craniosynostosis is the premature fusion of the cranial sutures. Craniosynostosis can occur as an isolated defect or as part of a syndrome. Craniosynostosis is called simple when only 1 suture is involved and compound when 2 or more sutures are involved.
Pathophysiology: In the recent literature, mutations in genes coding for fibroblast growth factor receptors (FGFRs) in affected families have been reported. The receptors mediate the effects of the fibroblast growth factors that modulate cellular processes, such as growth, differentiation, migration, and survival. FGFR2 mutations, located on chromosome 7, have been recognized in Crouzon disease and Apert, Jackson-Weiss, and Pfeiffer syndromes. Some cases of Pfeiffer syndrome and Crouzon disease involve mutations in both the FGFR1 and FGFR3 genes. These mutations account for a small fraction of cases of craniosynostosis, because most cases have an unclear etiology.
With the use of immunocytochemistry techniques, abnormal osteoblastic activity has been observed within the synostotic bone, along with decreased growth rate and alkaline phosphatase production. Histopathologic examinations of resected sutures demonstrate new bone formation at various stages. These stages range from trabecular interdigitation across the fibrous tissue to complete bony fusion.
Mortality/Morbidity: In most patients with craniosynostosis involving a single suture, the primary concern is
cosmetic. Early diagnosis and surgical therapy are essential to prevent lifelong craniofacial deformity. Patients with
diffuse craniosynostosis are at risk of developing increased intracranial pressure (ICP). Patients can have airway
problems because of a hypoplastic maxilla or ophthalmologic problems related to shallow orbits.
Anatomy: The bones of the cranium (frontal, parietal, temporal, and occipital) are well developed by the fifth month of gestation. The membranous skull bones are joined by connective tissue at the sagittal, coronal, metopic, lambdoid, and squamosal sutures. The anterior fontanel is at the junction of the frontal and parietal bones, and it represents the intersection of the metopic, coronal, and sagittal sutures. It normally closes in children by the age of 20 months. The posterior fontanel, located at the junction of the lambdoid and sagittal sutures, closes by the age of 3 months. Mature suture closure occurs by the age of 12 years, but completion of fusion continues into the third decade of life and beyond.
Clinical Details: Skull growth is restricted in the plane perpendicular to the prematurely fused suture and enhanced in the plane parallel to it.
Synostosis of the sagittal suture produces a long and narrow skull, called scaphocephaly or dolichocephaly. The anteroposterior diameter of the skull is increased, whereas the transverse diameter is decreased. Sagittal synostosis is seen most commonly in males. Although the biparietal diameter is low, the actual head volume is normal; therefore, no increase in ICP, no hydrocephalus, and no neurologic deficits are usually present. Associated anomalies are seen in 26% of patients.
Craniosynostosis. Sagittal synostosis. Markedly increased anteroposterior diameter of the head (dolichocephaly) with flattening of the superior contour is noted.
Synostosis of the coronal suture can occur bilaterally or unilaterally and is called brachycephaly and plagiocephaly, respectively. Brachycephaly results in a short, wide skull, with a shortened anteroposterior diameter with a flattened occiput and forehead. Brachycephaly is seen more commonly in females and has a higher incidence of neurologic complications, including increased ICP, optic atrophy, and mental retardation. (In contrast, isolated sagittal synostosis is usually associated with normal intellectual function.) A higher incidence of anomalies also is associated, ie, 33% when 1 suture is affected and as high as 59% when both coronal sutures are affected.
Craniosynostosis. Coronal synostosis. The anteroposterior diameter of the head is shortened (brachycephaly), with partially fused coronal sutures and a widened sagittal suture.
Craniosynostosis. Combined synostosis also demonstrating plagiocephaly. Anteroposterior view in a newborn with combined fusion of sagittal and coronal sutures
Synostosis of the lambdoid sutures is less common than sagittal and coronal synostosis. A marked flattening and underdevelopment of the posterior fossa are present, and overgrowth of the bregma may occur, resulting in a tall shape called oxycephalic or turricephalic skull.
Apert syndrome. Markedly deformed tower-shaped head resulting from premature fusion of all cranial sutures
Synostosis of the metopic suture occurs in utero. It is rare and called trigonocephaly. It results in a pointed forehead and hypotelorism, with an increased risk for associated anomalies of the forebrain. Other anomalies often encountered include cleft palate, coloboma, and a wide array of urinary tract abnormalities.
Trigonocephaly. Oblique view of the skull shows a ridge or keel in the midline of the frontal bone due to early fusion of metopic suture (arrow).
A combined synostosis of the coronal and sagittal sutures results in a severe form termed oxycephaly, which leads to microcephaly. In addition, increased ICP is associated with significant neurologic complications.
The most severe form is called the kleeblattschنdel deformity or cloverleaf skull, in which the coronal, sagittal, and lambdoid sutures are all affected. The skull resembles a cloverleaf shape, and patients typically have a bulging forehead, proptotic eyes, and severe neurologic impairment.
The most common syndrome-associated synostoses are Crouzon disease and Chotzen and Apert syndromes, which account for more than two thirds of syndrome-related craniosynostosis.
• Asymmetric craniosynostosis and plagiocephaly characterize Chotzen syndrome, which is inherited as an autosomal dominant trait and associated with facial asymmetry, ptosis of the eyelids, shortened fingers, a low frontal hairline, a long pointed nose, and soft tissue syndactyly. Cervical fusion is often seen at the level of the C2-C3 vertebrae.
• Crouzon disease is inherited as an autosomal dominant trait in 75% of patients, whereas the remaining cases are sporadic. The shape varies depending on the order of fusion, but it most commonly results in brachycephaly due to closure of the coronal and basal skull sutures. Associated findings include ocular proptosis, maxillary hypoplasia, parrot-beak nose, and ocular hypertelorism with normal limbs. Hydrocephalus is more common than in the other syndromes. Chronic tonsillar herniation is a common MRI finding that is seen in patients with Crouzon disease.
• Apert syndrome (acrocephalosyndactyly) is an autosomal dominant disorder characterized by coronal synostosis in conjunction with a malformed and short cranial base. It is associated with extensive syndactyly of the second, third, and fourth fingers (mitten hands), broad thumbs with radial deviation, toe syndactyly (sock toes), and visual impairment. Risk of mental retardation is increased; one half of patients have an intelligence quotient lower than 70. Cervical vertebrae fusion, primarily at the C5-C6 vertebrae, occurs in 68% of patients.
• Carpenter syndrome is inherited as a rare autosomal recessive trait and usually results in the
kleeblattschنdel deformity. Soft tissue syndactyly is always present in the hands and feet. Mental retardation is common.
o Pfeiffer syndrome is autosomal dominant and differs from Apert syndrome by the presence of polydactyly.
• Jackson-Weiss syndrome is mapped to the same gene as Crouzon disease. It results from coronal and basal skull synostosis. Associated findings include enlarged great toes and craniofacial abnormalities similar to those found in Pfeiffer syndrome but in the absence of the thumb abnormalities.
• Each syndrome has an increased risk of increased ICP, hydrocephalus, optic atrophy, respiratory problems due to a deviated septum, and disorders of speech and hearing. Surgical intervention
results in improved cosmetic appearance along with a substantially decreased risk of neurologic complications.
Increased intracranial pressure is frequently due to abnormalities of cerebral venous drainage as a result of maldevelopment of the foramina at the skull base.
Radiographic Findings: Plain radiographs are obtained easily and demonstrate osseous anatomy well. At a minimum, views should include anteroposterior (AP), Townes, and bilateral lateral films. Plain radiographs are useful for identifying the abnormalities of head shape (dolichocephaly, brachycephaly and plagiocephaly), which are characteristic of the various forms of craniosynostosis.
Plain radiographs can be used for the following:
• Identifying prematurely fused sutures (Normal sutures are seen on plain images as serrated, nonlinear, lucent lines. Sutures in patients with craniosynostosis are usually straight with sclerotic heaped-up margins or completely absent. The sclerotic margins may outline the sutures well and lead to the false impression that they are patent. Particular attention should be paid to the presence of this sclerotic margin and to focal sites of heaped-up margins, which are indicative of premature synostosis.)
• Demonstrating overall morphology of the cranium
• Identifying the presence of localized problems (constricting bony bands restricting growth)
• Identifying the presence of generalized problems (copper-beaten appearance, indicating elevated ICP)
• Identifying other skeletal anomalies.
CT Findings: CT scans provide a more detailed method for visualizing intracranial pathology and detailed anatomy of the calvaria and brain parenchyma. In contrast to plain radiographs, the skull base is visualized well. The relationship of hard and soft tissues of the craniofacial skeleton can be studied in detail.
• Neuroimaging is performed in children with isolated suture synostosis primarily to look for underlying brain damage or associated cerebral anomalies.
• Infants with trigonocephaly may have midline anomalies (eg, holoprosencephaly).
• Anomalies of the venous drainage and stenosis of the venous foramina at the skull base can occur with multisuture synostosis with both syndrome- and nonsyndrome-related causes.
• After abnormal or suggestive plain radiographic findings are noted, CT scans with bone windows with or without 3D reconstruction are frequently requested prior to surgical therapy.
• Features such as shallow anterior fossa, deformed dystopic orbits, abnormal calvarial contour, and asymmetric cranial base can be realistically depicted.
IV-Musculoskeletal system
1.Patient with generalized osteoporosis
Etiology:
Mechanism Causes
1) Immobilization Cerebral palsy – postencephalitis.
2) Endocrinal problems Cushing syndrome-Addisson disease-Cortizone treatment-hyperthyroidism.
3) Nutritional and metabolic. Rickets-scurvy-Vit d resistant rickets- Malabsorption(caeliac disease )
4) Constitutional Osteogenesis Imperfecta –Pyknodysostosis.
5) Blood dyscrasias Thalassaemia-Sickle cell anaemia
6) Renal osteodystrophy Renal tubular acidosis.
Fanconi syndrome
7) Immunodeficiency Buckley syndrome
2.Patient with a focal bony lesion
Criteria of evaluation :
1. Morphology :
Lesion matrix:
Cortex.
Periosteal reaction.
Soft tissue component.
2. Topography:
Longitudinal axi : epi ,meta or diaphyseal
Transverse axis: Central ,eccentric, cortical,juxtacortical.
3. Number:
Solitary
Multiple
4. Age:
Neonate
Infant
Older children.
Etiology :
A-Benign causes: Unicameral bone cyst,Osteochondroma ,chondroma ,Osteoid osteoma. B-Malignant causes : Ewing sarcoma ,Osteogenic sarcoma.
C-Aggressive non-malignant causes :Eosinophilic Granuloma-Aneurysmal bone cyst-Osteoblastoma-Chondroblastoma.
3-Limping Child
Etiology : The causes of limping in a pediatric age group can be classified according to the age of presentation into 3 categories :
I-1-4 years :
1. Congenital causes :Developmental dysplasia of hip joint .
2. Traumatic causes :
1. Non accidental injury.
2. Other lower extremity fractures.
3. Foreign body.
4. Toddler fracture
3. Infective/inflammatory causes :
a. Septic arthritis.
b. Osteomyelitis.
c. Transient synovitis of hip
d. Diskitis.
II-4-10 years :
1. Traumatic causes.
2. Infective:
a. Septic arthritis.
b. Osteomyelitis.
c. Transient synovitis.
d. Diskitis.
3. Inflammatry :
a. Juvenile rheumatoid arthritis.
4. Vascular :
a. Legg Calve-Perthe’s disease .
b. Blount disease.
III-10-15 years :
1. Traumatic
1.Stress fracture.
2.Osteochondritis dissicans.
2. Infective:
Septic arthritis.
Osteomyelitis.
3. Inflammatory
Jubenile rheumatoid arthritis.
4. Hormonal:
Slipped femoral capital epiphysis
Perthe’s disease:
Idiopathic osteonecrosis related to Legg-Calvé-Perthes disease is seen in children aged 3-12 years.
Ischemic cell death and necrosis of femoral head,which is the result of a reduced blood supply to the bone . Hematopoietic cells are sensitive to anoxia and are the first to die after reduction or removal of the blood supply; they usually die within 12 hours.
X-ray Findings: Plain radiographic findings in established osteonecrosis may be characteristic of the disease. In the
epiphyseal region, an arclike, subchondral, lucent lesion may be associated with areas of patchy loss of bone opacity
intermingled with sclerotic areas and bone collapse.
Steinberg has classified the radiologic appearance into 6 stages, as follows:
Stage 0 - Normal findings are demonstrated.
Stage I - The appearance may vary from normal to subtle trabecular mottling, but an isotopic bone scan or MRI show abnormal bone.
Stage II
Stage IIa - Focal radiopacity is associated with osteopenia.
Stage IIb - Radiopacity is associated with osteoporosis and an early crescent sign.
Stage III
Stage IIIa - An established crescent sign is associated with cyst formation.
Stage IIIb - Mild alteration in the configuration of the femoral head is due to a subchondral fracture, but the joint space is maintained.
Stage IV - Marked collapse of the femoral head is demonstrated with an associated acetabular abnormality.
Stage V - Joint space narrowing is demonstrated with changes of secondary osteoarthrosis.
CT Findings: demonstrate central or peripheral areas of reduced attenuation. Reformatted sagittal and coronal images show subchondral fractures and collapse of the articular surface.
MRI findings: MRI characteristics of bone infarction are variable focal abnormalities and are commonly demonstrated as patchy areas of low signal intensity on T1-weighted spin-echo images. Diffuse abnormal signal intensity may be present in osteonecrosis of the femoral head; these changes are reflected on both T1- and T2-weighted images.
The most characteristic appearance is the double-line sign, which consists of a hyperintense inner ring and a hypointense outer ring, on T2-weighted MRIs. This finding reflects the reactive interface between ischemic and nonischemic bone.
On T1-weighted MRIs, the interface appears as a low-signal-intensity line, which reflects a combination of granulation
tissue and, to a lesser extent, sclerotic bone. Gadolinium-enhanced short–inversion recovery images demonstrate
diminished enhancement in early infarctions of the femoral head.
Nuclear medicine findings: After acute osteonecrosis occurs, technetium-99m diphosphonate uptake can be absent after 72 hours. Subsequently, with revascularization and associated osteoblastic repair, intense activity is seen.
Coronal T1-weighted MRI in a 12-year-old boy with early Legg-Calvé-Perthes disease demonstrates slight irregularity of the right femoral capital epiphysis with abnormal signal intensity. The left hip appears normal.
Septic arthritis:
In general, infectious arthritis is classified as pyogenic (septic) or nonpyogenic. Pyogenic septic arthritis is most frequently caused by Staphylococcus aureus. It also may be caused multiple other organisms, including staphylococci, Gonococcus species, Haemophilus species, Klebsiella species, Pseudomonas species, and Candida species. Infection can lead to rapid and severe joint destruction.
Nonpyogenic infective arthritis tends to be less aggressive and have a more chronic course. Causative organisms include Mycobacterium tuberculosis, fungi, and spirochetes.
Septic arthritis can be acquired through several routes of transmission. The most common cause is hematogenous spread to a joint from a distant source such as pneumonia or a remote wound infection. Direct seeding from can occur through trauma, surgery, or spread from a contiguous infection such as osteomyelitis or cellulitis.
Pathophysiology: Infection of the synovial membrane precedes contamination of the synovial fluid in most cases. This lack of involvement of the synovial fluid is the proposed explanation for negative Gram stains and cultures that commonly occur in early infections. In response to the bacterial infection, the synovial membrane becomes edematous and hypertrophied. The synovium produces increased amounts of exudative fluid, and eventually, frank pus accumulates within the joint. Rarely, gas accumulates within the joint or adjacent soft tissues secondary to the presence of gas-forming organisms such as E coli.
The destruction of joint cartilage occurs secondary to the release of proteolytic enzymes in the synovial exudate. Abnormal fibrin deposition on the articular cartilage disrupts the nutrient supply, leading to further chondrolysis.
Rapid destruction of bone and cartilage is less characteristic of nonpyogenic mycobacterial and fungal infections probably because of lower concentrations of proteolytic enzymes in the joint exudate. However, tuberculous granulation tissue containing large numbers of leukocytes and macrophages can erode directly into cartilage or insinuate between the joint cartilage and subchondral bone, leading to detached cartilage and exposed subchondral bone.
In infants, septic arthritis is usually due to the hematogenous spread of disease, and it most commonly affects the hip. It may stem from perinatal infection of the umbilicus with hematogenous seeding of the femoral metaphysis. This leads to direct intra-articular extension due to the intracapsular location of the metaphysis. Increased intracapsular pressure reduces blood flow to the epiphysis, which can lead to ischemia compounding the damaging affects of the infection.
X-ray Findings:
Plain radiographic findings in the infant hip include obliteration of soft tissue planes, swelling, displacement of the fat pads, the obturator sign, and juxta-articular osteoporosis. Subluxation or dislocation of the femoral head secondary to intra-articular fluid can occur. However, this can be difficult to identify if the femoral head is not ossified.
In children, lateral displacement of the femoral epiphysis relative to the contralateral hip signifies a joint effusion. As little as 2 mm of asymmetry in the distance measured from teardrop of the acetabulum to the medial metaphysis of the femoral neck is considered pathologic.
A triad of radiographic abnormalities known as Phemister triad is characteristic of tuberculous arthritis: peripherally located bony erosions, juxta-articular osteoporosis, and gradual narrowing of the joint space.
Gas within the joint or adjacent soft tissues can sometimes be seen in infection secondary to gas forming organisms
such as E coli or Clostridium perfringens. However, gas within the joint is usually secondary to prior aspiration .
U.S.Findings: Ultrasonography is limited in the evaluation of septic arthritis. It is a sensitive modality for the detection of joint effusions in many anatomic locations. However, it is not reliable in characterizing the effusion or its cause. The thickness of the capsule and the echogenicity of the fluid are not good predictors of infection in the joint. Occasionally, ultrasonography can be helpful for guiding needle aspiration of the affected joint.
MRI Findings: MRI is a sensitive and relatively specific imaging modality for the evaluation of septic arthritis. Early in the infection, T2-weighted images demonstrate hyperintense fluid in the joint, as well as
increased signal intensity in the periarticular soft tissues and bones. MRI depicts the findings of more advanced disease, including articular cartilage damage and bony destruction. Tendon-sheath effusions, soft tissue cellulitis, and abscesses are also well depicted on MRIs.
Nuclear medicine Findings: Early-phase (blood flow) and later (blood pool) images show increased activity at the joint and on both sides of the affected area. Delayed images obtained at 4-6 hours should demonstrate continued increased activity in the bone with associated osteomyelitis.
Decreased uptake in the femoral head can be seen with decreased perfusion related to high intra-articular pressures from the joint effusion.
Coronal short-tau inversion recovery (STIR) MRI of the pubic symphysis demonstrates a hyperintense joint effusion and increased signal intensity in the bone marrow of the pubic rami. Abnormal high signal intensity is also present in the bilateral hip adductor muscles. The diagnosis was septic arthritis with associated osteomyelitis and inflammatory changes in the soft tissues.
Slipped Capital Femoral Epiphysis :
SCFE is a Salter-Harris type 1 fracture through the proximal femoral physis. Stress around the hip causes a shear force to be applied at the growth plate. Certainly, trauma has a role in the manifestation of the fracture, but an intrinsic weakness in the physeal cartilage also is present. The almost exclusive incidence of SCFE during the adolescent growth spurt indicates a hormonal role. Obesity is another key predisposing factor in the development of SCFE.
The fracture occurs at the hypertrophic zone of the physeal cartilage. Stress on the hip causes the epiphysis to move posteriorly and medially. Manipulation of the fracture frequently results in osteonecrosis and chondrolysis because of the tenuous nature of the blood supply.
Unlike typical Salter-Harris type I fractures, SCFE has a high propensity for morbidity. The nutrient vessels of the
epiphysis are beginning to penetrate the physis as it closes, and when the physis is disrupted, avascular necrosis of the
head may result, particularly if the head is manipulated. The tilted epiphysis is mechanically unfavorable and increases
weight bearing on the lateral edge.
Radiographic Findings: Diagnosis is made using AP pelvis and lateral frog-leg radiographs. Abduction of the femur for the frog-leg view may result in increased slippage and should be performed with caution.
On AP radiographs, pay close attention to the physis. Early in SCFE, the physis may widen. Increased opacity in the metaphysis, described as blanching, may occur as an early healing response, and the epiphysis may appear smaller because it is tilted dorsally.
The lateral radiograph demonstrates slippage earliest because the slippage begins with posterior displacement and progresses with medial rotation.
The patient has blanching of the metaphysis and only subtle widening of the physis. The epiphysis is yet to be displaced.
Frog-leg pelvic image in a child with bilateral slipped capital femoral epiphysis. A line perpendicular to the epiphyseal axis and another along the axis of the femoral neck demonstrate the degree of tilt by using the Southwick method.
Blount Disease
A brief overview of normal age-related angulation changes in the knee joint helps improve understanding the disease process. A pronounced varus angulation is seen in newborns and in children younger than 1 year. Varus angulation is believed to be secondary to in utero molding of the lower extremities, and this gradually resolves after children start walking. Varus angulation is usually corrected by the time children reach an approximate age of 18-24 months or after approximately 6 months of walking. From that time on, during the second and the third years, pronounced valgus angulation changes occur. The valgus position is partially corrected in the following years, reaching the adult pattern of mild valgus of the knees by age of 6-7 years. Thus, any varus angulation at the knee joint seen in individuals older than 2 years is abnormal; this finding is the basis for diagnosing tibia vara, or Blount disease.
Pathophysiology: The common denominator in tibia vara cases is abnormal stress placed on the posteromedial proximal tibial epiphysis that leads to growth suppression. Predisposing factors for the development of the condition include obesity, early walking, which exaggerate the impact of physiologic bowing and increase the stress placed on the physis of the proximal tibia.
As a result, altered mechanical forces in the proximal tibia lead to abnormal axial loading, which results in a change in direction of the weight-bearing forces from the perpendicular to the oblique. The oblique angle tends to displace the tibial epiphysis in a lateral direction, overloading the posteromedial segment and inhibiting its growth. A cycle of further longitudinal growth is established, and this results in progressive varus deformity. Therefore, unless the disease is diagnosed and treated early, the condition progressively worsens.
Types : Tibia vara has been recognized in 3 major types: infantile, juvenile, and adolescent. The most common type is infantile. Late-onset types may represent an unrecognized or untreated form of the infantile type or may occur after a neutral mechanical axis has been established.
Differential diagnosis:
Difficulty may be encountered in differentiating infantile tibia vara from physiologic bowing of the legs. However, the proximal tibial angulation is acute in Blount disease, occurring immediately below the medial metaphyseal beak. This feature results in a metaphyseal-diaphyseal angle greater than 11°. In physiologic bowing, angular deformity results from a gradual curve involving both the tibia and the femur.
Congenital bowing must be considered. The angulation may occur in the middle portion of the tibia, with a normal-appearing distal femur and proximal tibia.
Mild or healing rickets with residual bowing may be difficult to differentiate from stage 2 infantile tibia vara. However, rickets affects the skeleton in a generalized and symmetric fashion, with loss of the zone of provisional calcification in the physis. In addition, the typical biochemical abnormalities of rickets help in the differentiation of the conditions.
Ollier disease may result in tibial bowing but can be differentiated easily on radiographs by the presence of enchondromas.
Regarding growth-plate injuries of the proximal tibia may result in a deformity resembling tibia vara.
Osteomyelitis may be another mimic. Growth plate disturbance secondary to infection may result in an appearance similar to Blount disease.
In patients with metaphyseal chondrodysplasia, multiple metaphyseal deformities are seen, as is a short stature. Radiologically, the changes in this condition mimic those of rickets, but no abnormal serum biochemical results are noted.
X-ray findings : A standing anteroposterior radiograph of both legs is used to demonstrate bowing and abnormality at the medial aspect of the proximal tibia. In more advanced cases, bowing is seen at both ends of the tibia. On lateral knee radiographs, a posteriorly directed projection at the proximal tibial metaphyseal level is seen.
Different radiologic measurements have been used in an attempt to confirm the presence of the disease.
The metaphyseal-diaphyseal angle has been suggested to provide precise indications of Blount disease than the femoral-tibial angle. The metaphyseal-diaphyseal angle is obtained by measuring the angle formed between a line drawn parallel to the top of the proximal tibial metaphysis and another line drawn perpendicular to the long axis of the shaft of the tibia. Angle measurements are 9° ± 3.9° in cases of physiologic bowing and 19° ± 5.7° in patients with Blount disease. Reportedly, angles greater than 20° confirm true tibia vara in children . whereas angles of 15°-20° may or may not indicate tibia vara.
Bilateral Blount disease. Radiograph in a 2.5-year-old girl with bowing, which is more severe on the left. The proximal left tibia shows a medial beaking deformity. The metaphyseal-diaphyseal angles are 24° on the left and 14° on the right.
In 1952, Langenskiold first proposed a 6-stage classification of radiographic changes. This remains the most commonly used system. This classification was not intended for use in determining the prognosis or the most desirable type of treatment, and the author cautioned against such use. However, the fact remains that surgical treatment commonly is needed for any child with stage 3-6 changes.
Adolescent Blount disease. Moderate-to-severe changes in the proximal left tibia are demonstrated on this radiograph. Note the depression of the plateau, beaking, and metaphyseal sclerosis. The tibial growth plate
is widened and irregular. Note that the distal femoral growth plate shows changes as well. Mild irregularity and slight widening are seen.
Developmental dysplasia of hip joint :
Pathophysiology: DDH is the result of a disruption in the normal relationship between the acetabulum and femoral head. Without adequate contact between them, neither develops normally. At birth, the acetabulum has small bony and large cartilaginous contents, and the percentage of the femoral head covered by the acetabulum is less than that at any other time in development. Therefore, the first 6 weeks of an infant's life are critical to healthy hip joint formation, as McMillan et al reported.
Morbidity : The failure to diagnose and treat DDH in the immediate neonatal period can result in significant morbidity, including closed treatment failure, the need for open reduction, and the eventual development of osteoarthritis.
Possible complications of treatment include persistent dysplasia; recurrent dislocation; and, most significantly, avascular necrosis of the femoral head .
Sex incidence ;DDH is 4-8 times more common in female infants than in male infants. This difference is believed to be the result of the increased levels of circulating estrogens and relaxin.
Clinical findings: The Barlow maneuver is used to determine if a hip is dislocatable. The femur is flexed and adducted while posteriorly directed pressure is applied. This maneuver displaces an unstable hip from the acetabulum.
The Ortolani maneuver is used to reduce a dislocated hip. This is performed by abducting and flexing the femur, and palpable low-frequency clunk is noted as the femoral head slides back and reduces into the acetabulum
UltrasoundFindings:
The unossified cartilaginous femoral head appears as a speckled ball in the acetabular fossa. The femoral head should be centered in the joint space, with half or more medial to the baseline in the coronal plane. The extent of maturity of the acetabulum also can be quantified by using angular measurements. The standard coronal sectioning plane must be used at the deepest portion of the acetabulum, where the ilium appears as a straight line, perpendicular to the femoral head and parallel to the surface of the transducer.
In a complementary method of assessing acetabular development, the distance between the medial aspect of the femoral head and the baseline (d) is compared with the maximum diameter of the femoral head (D); this d/D ratio is expressed as a percentage. This ratio represents the coverage of the femoral head by the bony acetabulum in the standard coronal plane . Coverage of 58% or greater is considered normal. The smaller the coverage, the greater the acetabular immaturity.
Real-time coronal sonogram of the hip with calculation of the d/D ratio. Coverage of 58% or greater is considered
normal.
Coronal real-time sonogram of the hip obtained with stress maneuvering reveals significant lateral motion, which is not out of the plane of the baseline. This was accompanied by posterior motion in the transverse plane.
Limitations : Not all sonographically abnormal hips need treatment because many unstable hips may
spontaneously normalize within the first 2 weeks of a neonate's life, therefore delaying the first US study for 2
weeks is sound advice.
X-ray Findings: Plain radiographs of the pelvis are most helpful when significant ossification of the capital femoral epiphyses has occurred and when adequate US evaluation cannot be performed. Plain radiographs of the pelvis are obtained in the frontal projection with the legs in the neutral position. Before the femoral heads begin to ossify, the projected locations must be estimated.
Line measurements made on the anteroposterior radiograph help in determining the relationship of the femoral head with the acetabulum .
The acetabular angle is determined by drawing the Hilgenreiner, or Y-Y, line, which is a horizontal line between the 2 triradiate or Y-Y cartilages, and a second line connecting the superolateral and inferomedial margins of the acetabular roof, as Kirks and Griscom reported. The normal acetabular angle is approximately 28° at birth. The angle decreases gradually with age as a result of modeling of the acetabulum by the femoral head and as a result of the maturation of developing bone along the
superolateral acetabular roof. The acetabular angle often is increased in DDH because maturation and ossification of the acetabulum are abnormal and delayed.
The Perkins line is drawn at the outer acetabular margin and is perpendicular to the Hilgenreiner line. These lines divide the hip into quadrants. The unossified femoral head normally is centered in the inferomedial quadrant.
Frontal radiograph of the pelvis: The ossification centers of the capital femoral epiphyses are symmetric and located in the joint spaces. Both heads project in the inner lower quadrants formed by the intersection of the Hilgenreiner (H) and Perkin (P) lines. Shenton lines (S) are continuous and demarcated by the dashed lines. The acetabular angles are symmetric and less than 28° bilaterally.
In a normal hip, the Shenton line is a smooth unbroken arc that bridges the medial femoral metaphysis and the inferior edge of the superior pubic ramus. Displacement of the femoral head out of the joint space and disruption of the Shenton line is suggestive of DDH.
Delayed ossification of the femoral epiphysis is observed in the unstable hip. A false acetabulum eventually develops secondary to molding of the displaced ossification center against the bony pelvis.
Frontal radiograph of the pelvis in a 1-year-old child with a dislocated right hip: The degree of ossification of the femoral head on the dislocated side is decreased compared with that of the normally located left hip. The abnormally located hip articulates with a false neoacetabulum.
Osteochondritis Dissecans:
Pathophysiology: OCD is a form of osteochondrosis limited to the articular epiphysis. Both trauma and ischemia probably are involved in the pathology. Trauma may be caused by direct trauma or repetitive microtrauma . The pathology of OCD may be described in 3 stages.
In the first stage (acute injury), thickened and edematous intra-articular and periarticular soft tissues are observed
In the second stage, the epiphysis reveals an irregular contour and a thinning of the subcortical zone of rarefaction. On radiography, the epiphysis may demonstrate fragmentation.
The third stage is the period of repair in which granulation tissue gradually replaces the necrotic tissue. Necrotic bone may lose its structural support, which results in compressing and flattening of the articular surface.
Injury of the articular cartilage allows an influx of synovial fluid into the epiphysis, creating a subchondral cyst The subchondral cyst and increased joint pressure may prevent healing.
Knee: In the knee joint, the medial femoral condyle is the most commonly involved site
Elbow: In the elbow joint, the most common site of OCD occurs in the anterolateral aspect of the capitellum.
Ankle: In the ankle joint, OCD occurs more frequently in the talus than in the tibial plafond . The usual sites of OCD of the talar dome are the posteromedial aspect (56%) and the anterolateral aspect (44%) of the talus
Tarsal navicular: Occasionally, OCD of the tarsal navicular may be detected on ankle radiographs. Radiographic findings can be subtle and, in some patients, may mimic Muller-Weiss syndrome or stress fracture of the tarsal navicular. Tarsal navicular OCD does not demonstrate the classic radiographic appearance of Mueller-Weiss syndrome, which includes comma-shaped deformity of the navicular resulting from collapse of the lateral portion of the bone, bipartite navicular resulting from fracture, or protrusion of portions of the bone or the entire navicular bone, medially or dorsally. In addition, tarsal OCD does not demonstrate either partial or complete sagittal fracture line on CT or MRI.
Hip joint: In the hip joint, OCD occurs overwhelmingly in the femoral capital epiphysis. Shoulder joint: OCD rarely occurs in the shoulder joint, where it involves either the humeral head or the glenoid. Glenoid: OCD of the glenoid is best detected on MRI. A developmental defect of the glenoid is a normal variant that may be mistaken for OCD of the glenoid
Wrist joint: OCD of the wrist joint is rare and primarily occurs in the scaphoid.
X-ray Findings: On conventional radiographs, osteochondral lesions may appear normal. When detectable, osteochondral lesions appear as lucencies in the articular epiphysis. OCD is suggested by a loss of the sharp cortical line of the articular surface.
CT findings :In the ankle joint, helical CT has multiplanar capability. CT is obtained in the direct axial and coronal planes at 1.5-mm slice thickness with sagittal reformations. Cystic lesion of the talar dome, cortical depression, or a loose bony fragment within the osteochondral defect may be demonstrated.
Ferkel and Sgaglione CT Classification of Osteochondral Lesion of the Talus
Stage CT Findings
I Cystic lesion of the talar dome with an intact roof
IIa Cystic lesion with communication to the talar dome surface
IIb Open articular surface lesion with an overlying, nondisplaced fragment
III Nondisplaced lesion with lucency
IV Displaced osteochondral fragment
MRI Findings: MRI detects radiographically occult lesions that also may not be evident on CT. A short tau-inversion recovery sequence is the most sensitive.
Anderson MRI Classification of Osteochondral Lesion of the Talus
Stage MRI Findings
I Bone marrow edema (subchondral trabecular compression; radiograph results are negative with positive bone-scan findings)
IIa Subchondral cyst
IIb Incomplete separation of the osteochondral fragment
III Fluid around an undetached, undisplaced osteochondral fragment
IV Displaced osteochondral fragment
Sagittal T2-weighted image 1 year after injury reveals a subchondral cyst (arrow), an articular defect in the lateral tibial plateau, and a large knee effusion (arrowhead).
Axial CT of the knee demonstrates a completely detached osteochondral fracture (arrowhead) in the lateral aspect of the medial femoral condyle.
Coronal CT of the ankle demonstrates a nondisplaced osteochondral fragment.
Axial T2-weighted image of the ankle demonstrates subchondral bone marrow edema (arrowhead) in the proximal aspect of the tarsal navicular.
Coronal CT of the ankle demonstrates a cortical depression in the tibial plafond.
4-Child with upper limb trauma .
- Pediatric skeleton differs from adult in Anatomical, Biomechanical and physiological aspects.
-Physeal injuries are common,fractures can occur at the transition zone between woven and lamellar bones ,and healing process is much more rapid than adults.
-Detection of fractures depend on displacement of tissue planes ,abnormal alignment or width of cartilaginous zones.
Types :
1. Complete diaphyseal fracture.
2. Bowing fracture.
3. Incomplete linear fractures (Torus,greenstick )
4. Physeal fractures / Salter Harris injury.
Introduction:
The evaluation of pediatric elbow radiographs in the setting of acute trauma is challenging for many radiologists. Diagnostic difficulties stem both from the complex developmental anatomy of the elbow and from significant differences between children and adults in the patterns of injury after elbow trauma.
Understanding the developmental anatomy of the pediatric elbow helps ensure that normal ossification centers are not misinterpreted as fracture fragments, and it also helps the radiologist to recognize an injury when the pattern is altered. For example, the medial epicondyle is usually present before the ossification center for the trochlea appears. Therefore, when an ossicle is seen beneath the medial aspect of the distal humeral metaphysis and when the medial epicondyle is not seen in its expected location, the findings should be interpreted as demonstrating medial epicondyle avulsion with entrapment into the joint rather than a normal trochlea.
Knowledge of the expected patterns of injury aids in the recognition of subtle fractures because the radiologist knows what to look for in the bones and surrounding soft tissues. Understanding the mechanism of injury and the expected fracture pattern helps the radiologist supervising the examination to decide which additional views may be needed.
Anatomy :
The elbow is composed of 3 articulations. The ulna articulates with the humerus at the trochlea, which is the grooved and rounded medial articular portion of the distal humerus. The articular portion of the ulna is formed by the olecranon process proximally and by the coronoid process more distally. This humeroulnar or trochleoulnar joint is a hinged articulation that essentially permits motion in a single plane, allowing for flexion and extension. The concave head of the radius articulates with the capitellum, which is the convex lateral articular surface of the distal humerus. This humeroradial or radiocapitellar joint permits the radius to rotate to any degree of flexion or extension of the trochleoulnar joint, and this rotation allows supination and pronation of the forearm. Rotation also depends on proper motion of the proximal radioulnar joint (the third articulation of the elbow) and on the normal mobility of the forearm and wrist.
The distal humeral articular surface has several grooves and ridges that are important in determining anatomic stability after a fracture. Medially, the trochlear notch articulates with a corresponding ridge along the ulna. More laterally, the capitellotrochlear sulcus separates the humeral articular surface of the radius from that of the ulna. Between these grooves is the lateral crista of the trochlea, which provides lateral stability to the trochleoulnar joint.
Developmental anatomy
Ossification of the elbow region is complex, but knowledge of it is essential in analyzing elbow trauma in children. The distal humerus has 4 secondary ossification centers: those for the capitellum and trochlea (which form the articular surfaces) and those for the medial and lateral epicondyles. The capitellar ossification center extends beyond the capitellum so that the lateral crista of the trochlea is ossified from the capitellar center. Typically, none of these centers is ossified at birth.
Invariably, the capitellum is the first secondary center to ossify, usually followed by the medial epicondyle, the trochlea, and the lateral epicondyle. The age at which ossification centers are first seen varies considerably, and maturation usually proceeds earlier in girls than in boys. With this in mind, the average age at which the centers are seen first in 50% of children age 3 months for the capitellum, 5 years for the medial epicondyle, 8 years for the trochlea, and 10 years for the lateral epicondyle.
The corresponding ages at which the ossification centers of the proximal forearm bones appear are 4.5 years for the radial head and 9 years for the olecranon (Garn, 1967). The acronym CRMTOL is used to describe the usual order of appearance of all 6 elbow centers: capitellum, radial head, medial epicondyle,
trochlea, olecranon, and lateral epicondyle. These ossification centers vary not only in the patient age at development but also in their radiographic appearances.
The capitellum develops as a single smooth center, whereas trochlear ossification most often has a fragmented and irregular appearance. The medial epicondyle usually develops as a single center, and the lateral epicondyle can arise as either a single elongated center or as multiple centers of ossification. The lateral epicondyle usually fuses to the distal humeral epiphysis (lateral condyle) before fusing to the metaphysis. Ossification of the lateral epicondyle begins peripherally and progresses toward the epiphysis and metaphysis. The radial head ossification center is initially oval, and it subsequently becomes flattened and disk shaped. The olecranon is often ossified from 2 secondary centers that should not be misinterpreted as fracture fragments (and vice versa).
Evaluation of soft tissues and joint effusions
Evaluation of the soft tissues is important in elbow trauma. Localized soft tissue swelling over the lateral aspect of the elbow is a clue for which the radiologist should carefully search when assessing a possible lateral condyle fracture. Similarly, medial epicondyle avulsion fractures are often accompanied by localized soft tissue swelling in the medial aspect of the elbow.
Displacement of the elbow fat pads is an important indicator of an elbow joint effusion . The elbow fat pads are external to the synovium and present within the fibrous external joint capsule, with the posterior fat pad located in the olecranon fossa and the anterior fat pad located in the coronoid fossa. When the elbow is flexed, the posterior fat pad lies within the olecranon fossa, and it is usually not demonstrated on the lateral view. Hence, depiction of the posterior fat pad indicates outward displacement by a joint effusion. This evaluation is valid only when the elbow is flexed. With elbow extension, the olecranon process of the ulna moves into the olecranon fossa and displaces the posterior fat pad, which allows it to be depicted even without an effusion. The anterior fat pad may be seen just anterior to the distal humeral cortex as a normal finding, but if angled outward, it also indicates an elbow effusion.
If no fracture is seen and if a posterior fat pad sign is present, the index of suspicion for an occult fracture is high. However, the fat pad sign is not invariably present. The estimated frequency of occult fracture in these cases is 30-70%.
The presence of an elbow effusion alone does not indicate an etiology. In the setting of acute trauma, the presence of an elbow effusion strongly suggests a hemarthrosis resulting from a fracture. In other settings, the etiology may be different. Joint effusions due to septic arthritis or juvenile rheumatoid arthritis displace the fat pads, and patients with hemophilia often have an elbow hemarthrosis in the absence of fracture or trauma. In addition, other circumstances may involve a hemarthrosis but not displaced fat pads. If a fracture fragment disrupts a joint capsule, blood may escape from the joint, preventing joint distension and fat pad displacement. Marked edema may also obscure the fat pad, preventing recognition of the fat pad, even with displacement.
The implications of identifying an elbow joint effusion in the setting of acute trauma vary between children and adults. The identification of elbow joint effusions is more useful in children than in adults. In 70-90% of children, the presence of an effusion is associated with a fracture that is recognized either initially or on follow-up examinations. However, this percentage is not especially useful because, in most cases, the fracture is identified at the initial examination.
A more important question is related to the frequency of an occult fracture in patients with an elbow effusion (ie, when an effusion is present and when no fracture is seen on initial examination). In what percentage of patients is a fracture demonstrated later, either by recognizing demineralization at the fracture site or by recognizing the development of sclerosis or periosteal new bone formation during healing? Morewood estimated that the risk of occult fracture is approximately 30% (Morewood, 1987), although more recently, Skaggs and Mirzayan reported that the risk is 76% (Skaggs, 1999).
Determining which patients need to be treated for a presumed fracture is a clinical decision based on the examination results and knowledge of the associated risks. The absence of an effusion in children is strong evidence against an intra-articular fracture (Rogers, 1992). Although a torn capsule or marked edema may produce a false-negative fat pad sign, the presence of a significant injury is usually obvious on radiographs. In adults, a joint effusion is usually associated with a fracture; however, a significant number of fractures are not associated with an identifiable effusion. Therefore, the lower negative predictability of this sign makes it less useful in adults than in children.
Evaluation using lines drawn on radiographs
Two lines can be drawn on radiographs to help in evaluating elbow trauma: the anterior humeral line and the radiocapitellar line . On a true lateral view of the elbow, a line drawn along the anterior aspect of the distal humeral metaphysis should pass through the middle third of the capitellum, which is also part of the humerus. This anterior humeral line compares the position of 2 parts of the same bone; therefore, acute malalignment is indicative of a fracture. Specifically, if the anterior humeral line passes either through the anterior third of the capitellum or anterior to the capitellum, it indicates that the capitellum is displaced posteriorly relative to the humeral metaphysis. This displacement most frequently results from a supracondylar fracture, although posterior displacement of the capitellum may also be seen in lateral condyle fractures.
Although this sign is useful in interpreting findings in most children, caution is needed in young children. When the capitellar ossification center is small, the findings may not indicate the true center of the capitellum, most of which is still cartilage. If an early ossification center is located slightly posterior in the capitellar cartilage, the anterior humeral line may pass anterior to the ossification center, though the capitellum is not truly displaced. The exact stage of development at which the capitellum is sufficiently ossified for this sign to be reliable is not well defined; however, for children in the age range for supracondylar fractures (3-10 y), the capitellum is sufficiently developed, and interpreting this finding is not a problem.
The radiocapitellar line is used to evaluate the relationship of the proximal radius to the capitellum. Because the radius usually bends in the region of the tuberosity, the line should be drawn through only the most proximal part of the radius rather than along a greater length of the diaphysis. The line should intersect the capitellum on all views, although in young children, the capitellar ossification center may have an eccentric position within the largely cartilaginous capitellum. The radiocapitellar line is used to compare the relative positions of 2 adjacent bones; hence, malalignment between them indicates dislocation.
I-Supracondylar fracture
Supracondylar fractures are the most frequent elbow fracture in children, accounting for 50-60% of cases. Most occur in children aged 3-10 years, with a peak incidence in those aged 5-8 years. The fracture is located below the humeral shaft in the metaphysis. In this region, the humerus flares out into medial and lateral columns that extend into the condyles. Between these columns, the humerus is relatively thin at the olecranon and coronoid fossae. This thinning is most pronounced during childhood, with the trabeculae less well developed than in adults. This difference likely accounts for the greater frequency of supracondylar fractures in children (Wilkins, 1991).
The vast majority of supracondylar fractures are extension injuries and are due to a fall on an outstretched arm, with the proximal ulna transmitting force to the distal humerus. Relative ligamentous laxity in childhood allows the elbow to hyperextend, and with hyperextension, the olecranon transmits the load into a bending force on the distal humerus in the supracondylar region. Most supracondylar fractures involve posterior displacement or angulation of the distal fragment. Often, medial displacement accompanies supracondylar fractures. With medial displacement, loss of support for the medial aspect of the distal fragment allows the distal fragment to rotate into varus alignment. The less common supracondylar fractures that occur with anterior displacement of the distal fragment are usually caused by a direct blow to the posterior aspect of the elbow such as that sustained with a fall onto the elbow.
Radiographic findings
Supracondylar fractures are diagnosed with the help of radiographic findings by using both direct and indirect signs. The presence of a joint effusion does not specifically indicate that a fracture is present, but a joint effusion does signal that a fracture is likely, and a careful search is required. The anterior humeral line can be extremely useful in the diagnosis of supracondylar fracture; the line passes anterior to the middle third of the capitellum in 94% of cases.
Supracondylar fractures may be complete or incomplete and have a wide range of severity. The usual classification defines supracondylar fractures as follows:
• Type 1 - Fractures with no displacement
• Type 2 - Fractures with mild displacement or angulation and an intact posterior cortex
• Type 3 - Fractures with displacement and complete cortical disruption
With complete fractures, the fracture line and displacement are obvious. Even incomplete fractures often have enough disruption in 1 of the cortices (usually the anterior cortex) to make diagnosis easy . However, in approximately 25% of cases, the fracture may be subtle. These cases include greenstick and plastic bowing fractures. With greenstick fractures, cortical disruption is seen on the tensile side (usually the anterior cortex), and they may be accompanied by cortical buckling of the compression side (usually the posterior cortex). With plastic bowing, no discrete fracture line is present. Only deformity is observed, as demonstrated by the anterior humeral line. Subtle cortical deformity also may be present medially or laterally, and it may be associated with varus or valgus deformity.
In searching for subtle fractures, knowing their expected location is essential. On the frontal view, supracondylar fractures typically extend transversely through the metaphysis across the region of the olecranon fossa. With subtle fractures, the fracture line may be initially seen through only a portion of the metaphysis. With healing, sclerosis is demonstrated across the entire metaphysis, indicating the full extent of the fracture .
In the lateral projection, the fracture may be either transverse or oblique, typically extending from anterior and distal to posterior and proximal. Orientation of the fracture line in the sagittal plane has both diagnostic and clinical implications. Diagnostically, oblique fractures may be demonstrated more easily by using an AP view with cephalad angulation, which shows the fracture en face. Although not routinely acquired, this view may be useful when a fracture is highly suspected but not found on standard views. Clinically, an oblique fracture is important because it causes rotation at the fracture site to result in a varus or valgus deformity.
Complications
The 2 major complications of supracondylar fractures in children include cubitus varus , which is relatively common, and vascular injury, which is uncommon but has a considerable morbidity rate when present.
Cubitus varus is due primarily to alignment of the fracture at the time that it is set rather than to physeal injury leading to deformity from asymmetric growth. Because individual variation exists in the carrying angle, cubitus varus is best assessed by comparing the injured elbow with the contralateral side. This analysis is aided by the use of the Baumann angle, which is the angle between the humeral shaft and the distal humerus as defined by the growth plate between the capitellum and the metaphysis.
Although the physis in this region does not define the mechanical axis of the distal humerus, it serves as a well-defined marker that allows comparison of the orientation of the distal fragment to that of the contralateral elbow. Care must be taken to ensure a true AP view, because rotation leads to a change in the value of the Baumann angle. Although cubitus varus after supracondylar fractures is relatively common, in most instances, cubitus varus does not cause significant morbidity. In patients with more pronounced cubitus varus, corrective valgus osteotomy may be needed.
Vascular injury can be a severe complication of supracondylar fractures. With enough posterior displacement of the distal fragment, the brachial artery is subject to injury because it stretches across the fractured surface of the proximal fragment. Vascular insufficiency or swelling may lead to Volkmann ischemic contracture of the forearm, markedly limiting function of the extremity. Clinical assessment of vascular integrity at the time of presentation and after orthopedic manipulation as long as 48 hours later is
the key to preventing Volkmann ischemic contracture. Although plain radiographs are not useful in the evaluation of vascular injury. In some patients, arteriography, Doppler US, or CT angiography may be ordered to evaluate arterial flow and anatomy and to guide treatment, although the appropriateness of these studies is controversial.
Nerve injuries may also complicate supracondylar fractures, occurring in approximately 5% of patients. These injuries most frequently involve the anterior interosseous branch of the median nerve.
II -Lateral condyle fracture
Fractures of the lateral condyle are the second most frequent elbow fracture in children, accounting for approximately 15%. Lateral condyle fractures are seen most often in children aged 4-10 years. Many pediatricians and emergency physicians are not as familiar with these fractures as they are with supracondylar fractures, and some lateral condyle fractures may be subtle. As a result, the radiologist is useful in diagnosing lateral condyle fractures and in alerting the clinical staff to the features of the fractures and the need for orthopedic treatment.
Lateral condyle fractures have 2 primary mechanisms of injury. With a fall on an outstretched arm with the elbow extended and the forearm abducted, the radius transmits an axial load on the capitellum, causing the lateral condyle to fracture. More frequently, the fractures are the result of traction force. The lateral condyle is the origin of the forearm extensor muscles, and traction from these muscles can cause the lateral condyle to fracture when acute varus stress is applied to an extended elbow with the forearm supinated. In this position, the olecranon is locked in the olecranon fossa, with the trochlear ridge of the olecranon serving as the fulcrum of the varus stress. This mechanism accounts for the finding that the fracture line usually extends toward the trochlear groove of the distal humerus. It also accounts for the association of olecranon fractures with lateral condyle fractures.
Although controversy existed previously, lateral condyle fractures are currently considered to be Salter-Harris type IV fractures. The fracture line usually begins in the lateral aspect of the metaphysis and extends medially through the metaphysis and crosses the physis into the epiphysis.In most patients, the fracture involves only the cartilaginous portion of the distal humeral epiphysis; therefore, the epiphyseal component of the fracture is not seen on radiographs. In 4 of 48 patients in whom the fracture line passed across the physis into the ossified portion of the capitellum, the radiographic appearances were those of a Salter-Harris type IV fracture (Jakob, 1975)
More importantly, the presence of adjacent fractured bone margins of the metaphysis and epiphysis establishes the risk of bone bridging from the metaphysis to the epiphysis during healing. This bridging can cause focal growth plate closure, a recognized complication of Salter-Harris type IV fractures. For most patients in whom the ossified capitellum is not involved, the risk of focal growth plate closure is relatively low, similar to the risk in Salter-Harris type II or III fractures. The stability of the distal fragment is partly determined by whether the fracture extends all the way to the articular surface or whether a cartilaginous hinge remains intact to help prevent motion of the fracture fragment. In most patients in whom fracture extends to the articular surface, the fracture passes through the lateral portion of the trochlea so that the lateral crista of the trochlea is included in the fracture fragment, leading to instability of the trochleoulnar joint.
The Milch classification scheme for lateral condylar fractures defines type I fractures as those that pass through the ossified capitellum. These fractures enter the articular surface in the capitellotrochlear groove lateral to the lateral crista of the trochlea so that elbow stability is maintained (Milch, 1964). Milch type II fractures, the more common type, extend into the trochlea, leading to instability.
A staging system for classifying the severity of lateral condyle fractures is as follows:
• Stage I fractures are incomplete, with an intact cartilaginous hinge that may have some angulation but no true displacement.
• Stage II fractures are complete and have only a small amount of displacement of the distal fragment.
• With Stage III fractures, the distal fragment is significantly displaced, usually laterally and proximally, with instability of the elbow joint. In addition, traction from the common extensor muscles leads to rotation so that the cartilage-covered articular surface of the fractured lateral condyle is in contact with the metaphysis; this situation may result in malunion if not corrected.
Radiographic findings
The radiographic depiction of lateral condyle fractures depends on the degree of separation at the fracture site. If separation is significant, recognition of the fracture is easy. When no displacement is present, lateral condyle fractures may demonstrate subtle findings. A joint effusion helps in suggesting a subtle fracture, and lateral soft tissue swelling localizes the region to be examined most carefully.
Although posteriorly displaced lateral condyle fractures may show an abnormal relationship between the anterior humeral line and the capitellum, this finding is not as useful in lateral condyle fractures as in supracondylar fractures. These fractures often demonstrate only a subtle subcortical fracture line along the lateral aspect of the metaphysis. Therefore, only a very thin sliver of bone may be viewed; this finding represents the distal fragment that is otherwise primarily cartilage.
Oblique views may be required to depict these fractures, because they may not be seen on AP views. On lateral views, cortical disruption is usually seen posteriorly rather than anteriorly, as in supracondylar fractures.
Because several secondary ossification centers exist in the elbow, a small flake of bone adjacent to the metaphysis may be misinterpreted as a developmental center, such as the lateral epicondyle. However, because the lateral epicondyle is the last center in the elbow to ossify, most pediatric patients with lateral condyle fractures have elbows that are too immature to have a lateral epicondyle ossification center; therefore, the flake of bone must represent a fracture.
It may be tempting to regard such a subtle finding as too little to represent a significant fracture, and familiarity with these fractures is important in helping recognize them. However, note the following caution regarding subtle lateral condyle fractures: Partial overlap of the capitellum with the metaphysis may simulate a fracture when the lucency of the physis overlaps part of the metaphysis or when the double density of the capitellar and metaphyseal cortices simulates a fracture fragment.
Although a radiologic diagnosis in patients with lateral condyle fracture depends on plain radiographic findings, MRI, arthrography, or ultrasonography (US) may be useful in further evaluating the fractures, particularly with regard to the course of the fracture through the cartilaginous epiphysis. Other injuries that may be confused with lateral condyle fractures include supracondylar fracture and, in young infants, separation of the distal humeral epiphysis (transcondylar fracture, Salter-Harris type I).
Complications
The major complications of lateral condyle fractures in children include instability, malunion, and nonunion (leading to varus deformity or, less often, to valgus deformity over time). In the series by Jakob et al involving 48 patients with lateral condyle fractures, 20 patients had fractures that were minimally displaced, while 28 had significant displacement and required surgical reduction and fixation. Nonunion has been considered to be more of a problem in patients with minimally displaced fractures than in patients with significant displacement, presumably because the lack of surgical fixation allowed a small amount of motion and because of the development of fibrocartilage interposed between the fragments (Flynn, 1975). Delayed complications of lateral condyle fractures include ulnar neuritis and posttraumatic arthritis.
Lateral condyle fractures may be associated with other elbow fractures, particularly those involving the olecranon. However, they tend not to be associated with fractures remote from the elbow. Although lateral condyle fractures are associated with elbow dislocation, this is a direct result of the fracture, with loss of the stabilizing lateral crista as discussed above, rather than a separate injury.
III-Medial epicondyle fracture
Fractures of the medial epicondyle account for 10% of elbow fractures in children. They most often occur in children aged 7-15 years, with peak incidence in those aged 11-12 years. Approximately one half of medial epicondyle fractures are associated with elbow dislocation or subluxation. Medial epicondyle fractures are avulsion injuries caused by traction from the ulnar collateral ligament or the forearm flexor muscles that arise from the medial epicondyle.
The major mechanisms of injury include acute valgus stress during a fall on an outstretched arm, posterior stress with acute elbow dislocation, and chronic muscular traction from the flexor and pronator muscles such as that caused by throwing (eg, Little League elbow). Acute valgus stress may cause a compression injury on the lateral side of the elbow or a traction injury on the medial side. In adults, this stress most frequently causes a compression fracture of the radial head or neck, whereas in children, avulsion of the medial epicondyle is more common.
Radiographic findings
Medial epicondyle avulsions may include separation of the entire medial epicondyle from the metaphysis, avulsion of only part of the medial epicondyle or avulsion of the epicondyle plus a small portion of the adjacent metaphysis. These in injuries resemble Salter-Harris type I, III, and II fractures, respectively, though the Salter-Harris classification is usually applied to injuries of the epiphyses rather than those of the apophyses.
Owing to traction from the forearm flexors, the medial epicondyle is displaced distally. Also, it is usually medially displaced from its anatomic position . Localized soft tissue swelling is usually present. In most patients, the medial epicondyle is extra-articular; therefore, a joint effusion is not present. In some patients, the medial epicondyle may be intra-articular, and in others, widening of the physis for the medial epicondyle may be subtle. Comparison views of the contralateral elbow may be useful.
Complications
The fractured medial epicondyle may become entrapped in the elbow joint, representing a major complication. With acute valgus stress, the medial side of the elbow joint is opened. When the medial epicondyle is pulled downward (distally) by the forearm flexor muscles, it may enter the medial joint space. When the valgus force is removed, the medial epicondyle may then become entrapped as the medial joint space closes.
Entrapment is particularly common after an elbow dislocation or subluxation. Recognition of such entrapment is important in making a diagnosis by using radiographic findings. This process is aided with the radiologist's familiarity with the normal developmental anatomy of the elbow. Because the entrapped medial epicondyle is positioned beneath the medial side of the distal humeral metaphysis, it may be misinterpreted as the ossification center for the trochlea. However, the trochlea does not become ossified prior to the medial epicondyle. Therefore, the trochlea should not be seen unless the medial epicondyle is identified as well. In addition, usually, the trochlea initially appears as multiple fragmented ossification centers compared to the smooth and regular appearance of the medial epicondyle.
An entrapped medial epicondyle may be difficult to detect on the frontal view and is often better depicted on the lateral view. A clue to an entrapped medial epicondyle on the frontal view is widening of the medial joint space. However, widening of the joint space may be difficult to evaluate in patients in whom the elbow is immature when the largely cartilaginous trochlea makes the normal gap between the distal humerus and ulna appear quite wide.
In the radiographic evaluation of pediatric elbow trauma, assessing the status of the medial epicondyle is important, particularly after an elbow dislocation. If the elbow is mature enough for ossification of the medial epicondyle to be expected, the position of the medial epicondyle should be verified. If the medial epicondyle is not seen in its normal anatomic position, it should be searched for elsewhere, including within the elbow joint.
Avulsion fractures of the medial epicondyle may occur prior to ossification, and they cannot be detected on plain radiographs. However, such an injury may be suggested by localized tenderness and soft tissue swelling and by the presence of a posterolateral elbow dislocation. Stress radiographs demonstrating widening of the medial joint space with valgus stress indicate either avulsion of the medial epicondyle or disruption of the ulnar collateral ligament. In children, the ligaments are generally stronger than the bone; therefore, avulsion fractures occur more frequently than ligamentous injury, as with medial epicondyle injuries. MRI is useful in identifying these fractures. Conventional, magnetic resonance, or CT arthrography may be helpful in searching for a cartilaginous entrapped medial epicondyle in patients in whom the medial epicondyle is intra-articular.
IV-Medial condyle fracture
Fracture of the medial condyle is an uncommon injury in children. Similar to lateral condyle fractures, these are typically Salter-Harris type IV injuries. The fracture extends through the metaphysis and into the epiphysis, typically arising just above the medial epicondyle and extending to the trochlear groove .
In young patients with a nonossified or only partially ossified trochlea, the epiphyseal component of the fracture is not visible, and only the metaphyseal flake is identified. The medial epicondyle is included in the distal fragment. Similar to lateral condyle fractures, medial condyle fractures have a high risk of instability and may be complicated by nonunion. Although differentiating medial condyle from medial epicondyle fractures is important, the distinction is not always easy with radiographs.
The presence of a metaphyseal flake fracture is not specific because some medial epicondyle avulsions may extend into the metaphysis as a Salter-Harris type II fracture. In general, medial condyle fractures (Salter-Harris type IV injuries) have larger metaphyseal components than medial epicondyle fractures that involve the metaphysis. Medial condyle fractures are more likely to have a joint effusion, although joint effusions may be seen with medial epicondyle avulsion fractures. Clinical features that suggest a medial condyle fracture include instability and a limitation of elbow motion.
V-Transcondylar fracture
The term transcondylar fracture is used for fractures that separate the entire distal humeral epiphysis from the metaphysis. In most patients, these fractures occur entirely through the growth plate, resulting in a Salter-Harris type I fracture, although the fracture may extend into the metaphysis with a Salter-Harris type II injury. Transcondylar fractures most often occur in young children (<2 y), and they are reportedly associated with birth injury and child abuse. The mechanism of injury is believed to be rotational shear (Bright, 1974).
In a transcondylar fracture, the epiphysis is usually medially displaced relative to the metaphysis. The proximal radius and ulna maintain a normal relationship to the epiphysis; hence, the forearm bones are also displaced relative to the humeral metaphysis. In young children in whom the distal humeral epiphysis is not yet ossified, this malalignment of the forearm bones and the distal humeral metaphysis causes confusion with an elbow dislocation. Often, the capitellum has ossified, allowing it to serve as an important marker in the otherwise cartilaginous distal humeral epiphysis.
Demonstration of normal alignment between the proximal radius and the capitellum (radiocapitellar line) and normal alignment of the proximal radius and ulna with each other are the keys to differentiating transcondylar fracture from elbow dislocation. If the capitellum is not ossified and if it cannot be used to evaluate elbow alignment, medial displacement of the forearm bones relative to the distal humeral metaphysis should suggest a transcondylar fracture because the distal fragment is usually displaced medially. Conversely, in true elbow dislocations, the radius and ulna are dislocated either laterally and posteriorly (in children >2 y) or primarily posteriorly (in children <2 y). MRI, US, or arthrography may be used to directly depict the relationship of the cartilaginous distal humeral epiphysis to the metaphysis.
Some transcondylar fractures include a small portion of the metaphysis, which is helpful in recognizing that a fracture is present . However, this finding may cause the injury to be confused with a lateral condyle fracture. The distinction of the 2 fractures is important because lateral condyle fractures are often unstable and require operative fixation, which is frequently not necessary for transcondylar fractures because of its greater stability after reduction.
Features that help in distinguishing the 2 fractures include alignment of the radiocapitellar joint and the direction of displacement. In transcondylar fractures, radiocapitellar alignment remains normal, whereas in lateral condyle fractures, the distal fragment is often displaced or rotated as described above, with alteration of the radiocapitellar alignment. Because the lateral crista of the trochlea is often included in the fracture fragment, the elbow joint loses lateral support in lateral condyle fractures. Lateral displacement of the proximal forearm bones results, rather than the medial displacement that typically seen in transcondylar fractures.
In most cases, patients with transcondylar fractures have a good prognosis, although diagnosis and treatment are precarious. In some patients, impaction of the epiphysis on the medial aspect of the metaphysis may cause growth plate injury, leading to subsequent varus deformity. Keep in mind the association of transcondylar fracture with child abuse.
VI-Fractures of the proximal radius
Although the proximal radius is the most common site of elbow fracture in adults, it accounts for only 5% of elbow fractures in children. When proximal radial fractures occur in children, they primarily involve the radial neck. Fractures of the radial head epiphysis are uncommon in children.
Fractures of the proximal radius are usually caused by a compression force from a fall on an outstretched hand. The normal valgus at the elbow transforms this initial axial load into both axial and valgus stress. In adults, this stress leads to a high incidence of radial head and neck fractures, whereas in children, valgus stress more frequently causes a distraction injury on the medial side of the joint. When valgus stress does cause a proximal radial fracture in children, the compression stress usually causes fractures through the metaphysis (radial neck) rather than the epiphysis (radial head), which is largely cartilaginous.
Radiographic findings
Most proximal radial fractures in children are either Salter-Harris type II injuries that extend through the growth plate and the lateral aspect of the metaphysis or metaphyseal fractures that extend across the neck near the growth plate, but they do not involve the growth plate directly. Rarely, a Salter-Harris type IV fracture extends vertically through the metaphysis and epiphysis, crossing the physis. With some proximal radial fractures, no displacement of the epiphysis occurs, and detection of the fracture depends on the metaphyseal component, which may show only subtle abnormal angular deformity. This finding must be distinguished from the normal angulation that is usually present at the junction of the radial neck and shaft .
The radial head epiphysis may also show displacement with varying amounts of shift and angulation that may lead to limitation of motion of the proximal radioulnar joint (Wedge, 1982). Proximal radial fractures may result in abnormal articulation of the radial head and capitellum and therefore are fracture/dislocations. Displacement of the radial head may be marked, usually with the head displaced distally, and its articular surface may be rotated into the coronal plane posteriorly. However, the displacement may also be lateral .These cases may be due to transient posterior elbow dislocation.
When the proximal radius and ulna then are forced anteriorly and the dislocation is reduced, the capitellum may shear off the radial head, leaving it posteriorly displaced. During the reduction of these completely displaced fractures, the radial head may become inverted so that the physeal fracture surface of the radial head articulates with the capitellum. Less often, as the proximal radius and ulna are dislocating posteriorly, the capitellum may cause the radial neck to become fractured, and it may force the radial head anteriorly and distally.
Complications
A major complication of a radial neck fracture is limitation of motion at the proximal radioulnar joint, which mostly limits supination. This complication is usually caused by malalignment of the radial head and neck, and more severe limitation of motion may be caused by radioulnar synostosis. Radial head displacement or injury to the proximal radial growth plate may also cause growth arrest, leading to radial shortening that may affect the wrist joint. Proximal radial fractures in children have a high association with other injuries, which most frequently involve the olecranon. The identification of a proximal radial fracture should alert the examiner to carefully search for other injuries
VII-Fractures of the proximal ulna
Fractures of the proximal ulna are uncommon in children, accounting for 6% of elbow fractures. In evaluating the proximal ulna in children, the normal olecranon apophysis must not be mistaken for a fracture fragment. The olecranon apophysis usually appears in children aged approximately 10 years, and it fuses by age 18 years. The normal apophysis may have separate ossifications centers near its tip.
The olecranon apophysis fuses in an anterior-to-posterior direction, and radiographs may reveal a residual posterior cleftlike lucency with well-defined sclerotic margins. The characteristic location of the olecranon ossification centers, their smooth uninterrupted cortical margins, and the typical appearance of the partially fused physis help in distinguishing olecranon ossification from fractures at that site.
Most proximal ulnar fractures involve the olecranon process. The 3 major mechanisms of injury include direct impaction; distraction stress from the triceps muscles; and valgus or varus stress with the elbow in extension, which locks the olecranon into the distal humerus.
Radiographic findings
Distraction stress on the olecranon may occur from falling on an arm with the elbow partially flexed so that acute hyperflexion stress is applied against the triceps or from excessive muscular activity, which is often associated with throwing. Distraction fractures have a particularly high incidence in patients with osteogenesis imperfecta, including patients with relatively normal-appearing bones and few fractures elsewhere. Distraction fractures of the olecranon may be subtle, or they may have significant proximal displacement of the fracture fragment. These fractures are usually Salter-Harris type II injuries that include a metaphyseal fragment of variable size. Salter-Harris type I fractures that pass entirely through the physis of the olecranon apophysis may occur, but they are relatively uncommon. The detection of these fractures requires a high index of suspicion and comparison with the noninjured elbow.
When the elbow is fully extended, the olecranon becomes locked into the olecranon fossa, making it susceptible to fracture by varus or valgus stress. These fractures may be subtle and have only a linear lucent line through the trabecular region. In other patients, the fracture is best seen at the proximal tip of the olecranon metaphysis.
Complications
Valgus stress fractures may be associated with compression fractures of the radial neck or avulsion of the medial epicondyle. Varus stress fractures may be associated with a lateral condyle fracture or a lateral dislocation of the radial head (type 3 Monteggia fracture/dislocation).
Olecranon fractures have a high incidence of associated injuries, which are believed to have the highest association with proximal radial fractures, although several are associated with lateral condyle fractures.
Fractures of the coronoid process are infrequent in children, but they may be seen with posterior elbow dislocation.
VIII-Elbow dislocation
The elbow is the most frequently dislocated joint in children, whereas in adults, dislocations of the shoulder and interphalangeal joints of the fingers are more common. Elbow dislocation accounts for approximately 5% of elbow injuries in children. The mechanisms of dislocation include a fall on an outstretched arm with the elbow partially flexed and forced hyperextension, although both mechanisms more frequently result in fractures than in dislocations. The most common direction of displacement is posterior , although lateral and anterior dislocations also occur.
Dislocations often are associated with fractures, most often involving the medial epicondyle and coronoid process of the ulna. Other fractures that may be associated with elbow dislocations include fractures of the proximal radius, particularly fractures in which the radial head is markedly displaced and rotated into the coronal plane; fractures of the lateral condyle; and remote fractures in the same extremity, most often the distal radius and ulna. Detection of an elbow dislocation should alert the radiologist to carefully search for the other injuries.
Radiographic findings
Elbow dislocations are usually readily apparent on radiographs. In young patients, alignment of the radiocapitellar joint is evaluated by using the radiocapitellar line, whereas in the more mature skeleton, articulating surfaces of the radial head and capitellum are revealed directly. The articular relations of the medial condyle and proximal ulna are not as easy to evaluate in the immature skeleton.
After spontaneous reduction, prior elbow dislocation can be suggested by the identification of the fractures described above. In patients younger than 2 years, elbow dislocations are exceedingly rare, and transcondylar fracture (distal humeral epiphyseal separation) is often mistaken for elbow dislocation. Radiographic findings that indicate transcondylar fracture rather than dislocation include maintenance of normal radiocapitellar relations and medial displacement of the forearm bones.
Complications
Complications of elbow dislocation in children include associated fractures, neurologic injury (usually involving the ulnar nerve or the anterior interosseous branch of the median nerve), joint contracture, and heterotopic ossification in the regions of the disrupted medial or lateral collateral ligaments. Vascular complications are less common than neurologic injury and are usually accompanied by severe injuries, often including open fractures (Wheeler
IX-Monteggia fracture/dislocation
Monteggia fracture/dislocation involves dislocation of the radial head accompanied by fracture of the proximal or mid ulna, with the apex of the ulnar fracture pointing in the same direction as the radial head dislocation. Normal articulation of the medial condyle and proximal ulna is maintained. In 55-85% of patients, the radial head is anteriorly dislocated, with an associated apex anterior ulnar fracture (Monteggia type 1 injury). In the remainder of patients, fractures/dislocations are divided equally between posterior (Monteggia type 2 injury) and lateral (Monteggia type 3 injury) dislocation of the radial head. Lateral (Monteggia type 3) injuries most often occur in children aged 5-9 years .
Simplistically, a Monteggia fracture/dislocation can be thought of as the result of a force that dislocates the radial head and simultaneously fractures the ulna in the same direction. However, in most patients, the injury is due to a fall onto a pronated forearm, which forces the arm into hyperpronation. This motion causes the ulna to fracture and contact the proximal radius, forcing the radial head to become dislocated from the capitellum.
In children, an ulnar fracture often may be manifested by plastic bowing without a discrete fracture line .In some patients, the finding may be subtle, and recognition of this injury requires a high index of suspicion and the use of comparison views of the contralateral forearm when needed. Most cases of isolated radial head dislocation in children are likely to actually be Monteggia fracture/dislocation with a subtle ulnar bowing fracture. Conversely, ulnar fractures in a child are often accompanied by a radial fracture or dislocation, even if the ulnar fracture is a relatively subtle greenstick injury. If an associated radial fracture is not identified, a careful search should be made for a radiocapitellar dislocation or subluxation. The elbow should be well visualized in all patients who have an ulnar injury with or without associated radial fracture.
A Monteggia variant has fractures of the radius and ulna. The radial fracture is so close to the joint that the injury that it may superficially resemble a radial head dislocation. In these cases, only the radial head is still in alignment with the capitellum. The rest of the radius appears dislocated with respect to the capitellum; however, this is a displaced fracture rather than a dislocation. In cases in which the radial head is not yet ossified, this injury cannot be distinguished from a true Monteggia fracture/dislocation by using plain radiographs.
A similar situation occurs in the wrist in children, that is, a fracture through the distal ulnar physis may occur in association with a distal radial diaphyseal fracture and result in a pseudo-Galeazzi injury. In fact, Monteggia variant and pseudo-Galeazzi injuries are forearm fractures involving both bones, with 1 of the fractures occurring so close to the joint that a dislocation is erroneously suggested.
X-Pulled elbow
A pulled elbow is a distraction injury. It is also called nursemaid's elbow and other names, and it usually results from a sudden pull on the hand. In children younger than 5 years, the annular ligament is relatively loose, allowing the radial head to be pulled through it when acute traction is suddenly placed on a pronated forearm (which is the usual position of the forearm when a child is being pulled along by an adult). Although the annular ligament becomes transiently interposed between the radial head and capitellum, this movement does not cause recognizable widening of the radiocapitellar joint. Therefore, elbow radiographic findings are normal in a pulled elbow. MRIs should demonstrate the abnormal relationship of the radial head and annular ligament, but such studies are seldom needed.
Summary :
Radiographic evaluation of acute elbow trauma in children can be difficult because of the multiple ossification centers that appear in this region. However, acute elbow trauma provides an excellent example of how an understanding the developmental anatomy of the region plus knowledge of the mechanism of injury and the most frequent fracture patterns and associations can greatly aid in the radiographic analysis.
Fat pad signs indicate an elbow joint effusion. Lateral view shows the posterior fat pad, which is always abnormal when seen with the elbow positioned in right-angle flexion.
Typical supracondylar fracture. Anteroposterior (A) and lateral (B) views. Note the abnormal relation of anterior humeral line and the lateral view.
Supracondylar fracture. Cubitus varus. A, Anteroposterior view shows a varus deformity of the distal humerus from a previous well-healed supracondylar fracture. B, On the lateral view, the capitellum remains
posteriorly positioned, a finding typical of a previous supracondylar fracture.
Displaced lateral condyle fracture.
Medial epicondyle fracture with entrapment in an 8-year-old boy. Anteroposterior (A) and lateral (B) views of the injured right elbow compared with anteroposterior (C) and lateral (D) views of the uninjured left elbow.
Note the normal position of the medial epicondyle in left elbow, which is not seen in the right elbow.
Radial neck fracture. Anteroposterior view shows a mildly abnormal angular configuration of the lateral aspect of the proximal radial metaphysis. This finding is indicative of a nondisplaced fracture.
Monteggia variant. Anteroposterior (A) and lateral (B) views. An ulna fracture with apex anterior angulation is
present. Apparent anterior dislocation of the proximal radius, as seen on the lateral view, is actually a proximal radial fracture with anterior displacement of the neck and shaft relative to the poorly visualized
radial head that still articulates normally with the capitellum.
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