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Thorax. Internal thoracic artery descends into thorax 1.2cm lateral to edge of sternum, and ends at the sixth costal cartilage by dividing musculophrenic and superior epigastric arteries. Azygos vein Begins as continuation of right ascending lumbar vein - PowerPoint PPT Presentation
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Thorax
Internal thoracic artery descends into thorax 1.2cm lateral to edge of sternum, and ends at the sixth costal cartilage by dividing musculophrenic and superior epigastric arteries
Azygos vein Begins as continuation of right ascend
ing lumbar vein Ascending along the right side of vert
ebral column Joins superior vena cava by aching a
bove right lung root at level of T4 to T5
Receives right posterior intercostals and subcostal veins plus some of bronchial, esophageal and pericardial veins, and hemiazygos vein
Tributaries – hemiazygos v. and accessory hemiazygos v., which receive most left posterior intercostals vein and left bronchial veins
The lymphatic drainage of thoraxThe lymphatic drainage o
f thoracic wall To axillary lymph nodes To parasternal lymph nodes
(along internal thoracic vessels)
To intercostals lymph nodes from deeper structures
lymph nodes of the thoracic contentslymph nodes of trachea, bron
chi and lungs Pulmonary lymph nodes lie in th
e angles of bifurcation of branching lobar bronchi
Bronchopulmonary hilar lymph nodes - lie in the hilus of the lung
Tracheobronchial lymph nodes
- situated above or below the bifurcation of trachea
Paratracheal lymph nodes - along each side of the trachea
Anterior mediastinal lymph node lies anterior to the large blood vessels of thoracic cavity and pericardium; the efferents unite with those of paratracheal lymph nodes, to form the right and left bronchomediastinal trunks. The left bronchomediastinal trunk terminates in thoracic duct, and right in the right lymphtic duct
Posterior mediastinal lymph nodes lie along the esophagus and thoracic aorta
Anterior branches of thoracic nerves Intercostal nerves - (anterior rami of
T1- T11): runs forward inferiorly to intercostals vessels in costal groove of corresponding rib, between intercostals externi and intercostals interni; first six nerves are distributed within their intercostals space, lower five intercostals nerves leave anterior ends of their intercostals spaces to enter abdominal wall
Subcostal nerve - (anterior ramus of T12): follows inferior border of T12 rib and passes into abdominal wall
Distribution: distributed to intercostales and anterolateral abdominal muscles, skin of thoracic and abdominal wall, parietal pleura and peritoneum
The segmental innervation of anterior surface of trunk T2 - sternal angle T4 - nipple T6 - xiphoid process T8 - costal arch T10 - umbilicus T12 - midpoint between u
mbilicus and symphysis pubis
Phrenic nerve Descends over scalenus ante
rior to enter thorax Accompanied by pericardioph
renic vessels and passes anterior to lung roots between mediastinal pleura and pericardium to supply motor and sensory innervation to diaphragm
Sensory fibers supply to pleurae, pericardium and peritoneum of diaphragm; usually right phrenic nerve may be distributed on live, gallbladder and biliary system.
Left vagus nerve Enter thoracic inlet between left com
mon carotid and left subclavian arteries, posterior to left brachiocephalic vein
Crosses aortic arch where left recurrent laryngeal nerve branches off
Passes posterior to left lung root Forms anterior esophageal plexus Forms anterior vagal trunk at esopha
geal hiatus where it leaves thorax and passes into abdominal cavity , then divides into anterior gastric and hepatic branches
Right vagus nerve Enter thoracic inlet on right side
of trachea Travels downward posterior to ri
ght brachiocephalic vein and superior vena cava
Passes posterior to right lung root
Forms posterior esophageal plexus
Forms posterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches
Recurrent laryngeal nerves Right one hooks around right subcl
avian artery, left one hooks aortic arch
Both ascend in tracheo-esophageal groove
Nerves enter larynx posterior to cricothyroid joint, the nerve is now called inferior laryngeal nerve
Innervations: laryngeal mucosa below fissure of glottis , all laryngeal laryngeal muscles except cricothyroid
Bronchial and esophageal branches
Thoracic sympathetic trunk Branches of sympathetic trunk to thoraci
c plexuses Greater splanchnic nerve - formed by
preganglionic fibers from T5~T9 ganglia, and relay in celiac ganglion.
Lesser splanchnic nerve - formed by preganglionic fibers from T10~T12 ganglia, and relay in aorticorenal ganglion.
The postganglionic fibers supply the liver, spleen, kidney and alimentary tract as far as the left colic flexure.
Regional anatomy of thorax
Parts and regions of the thoraxBoundaries Superior - jugular notch, ste
rnoclavicular joint, superior border of clavicle, acromion, spinous processes of C7
Inferior - xiphoid process, costal arch, 12th and 11th ribs, vertebra T12
Regions Thoracic wall Thoracic cavity
Landmarks Jugular notch corresponds with
The 2th thoracic vertebra in male, the 3th thoracic vertebra in female
Sternal angle connects 2nd costal cartilage laterally corresponds with The lower border of 4th thoracic ve
rtebra The bifurcation of trachea in the ad
ult The beginning of aortic arch which
ends posteriorly at the same level The esophagus is crossed by the l
eft main bronchus
Xiphoid process - xiphisternal junction lies opposite the body of the 9th thoracic vertebra
Clavicle Inferior fossa of clavicle Coracoid process
Ribs and intercostal spaces Costal arch
Infrasternal angle Xiphocostal angle
Papillae
Thoracic wall
Skin Superficial fascia
Thoracoepigastric v. Supraclavicular n. Anterior and lateral cutan
eous branches of intercostal n.
Deep fascia
Lymphatic drainage of breast
Into pectoral ln. from lateral and central parts of breast
Into apical and supraclavicular ln. from superior part of breast
Into parasternal ln. from medial part of breast
Into interpectoral ln. from deep part of breast
The lymphatic capillaries of breast form an anastomosing network which is continuous across the midline with that of the opposite side and with that of the abdominal wall
Internal thoracic vessels Internal thoracic a.&v. Parasternal ln.
Endothoracic fascia
The muscles of thoraxExtrinsic muscles Pectoralis major Pectoralis minor Serratus anteriorIntrinsic muscles Intercostales externi Intercostales interni Intercostales intimi Transverses thoracis
Intercostales externi Origin: lower border of ri )Ⅱ Insertion: upper border of rib b
elow origin Action: elevate ribs adding in f
orced inspiration Replaced anteriorly by external
intercostals membrane.
Intercostales interni Origin: upper border of rib Insertion: lower border of rib a
bove origin Action: depress ribs for forced
expiration Replaced posteriorly by interna
l intercostals membrane.
Intercostal space
Posterior intercostal v.
Posterior intercostal a.
Intercostal n.
Diaphragm Shape and position: do
me-shaped between thorax and abdomen, consists of a peripheral muscular part and a central tendon
Origin Sternal part: xiphoid process Costal part: lower six and costal cartila
ges Lumbar part: arises by two crura from
upper 2-3 lumbar vertebrae Insertion: central tendon
Weak areas: triangular spaces without muscular tissue
Lumbocostal triangle: between costal and lumbar parts.
Sternocostal triangle: between costal and sternal parts.
Openings in the diaphragm Aortic hiatus - lies anterior to the body of the 12th thoracic v
ertebra between the crura. It transmits the aorta, thoracic duct
Esophageal hiatus - for esophagus and vagus nerves at level of T10.
Vena cava foramen - for inferior vena cava, through central tendon at T8 level
T8
T10
T12
Action: Contraction: the dome
moving downward, increases the volume of thoracic cavity which results in inspiration, at the same time the intra-abdominal pressure is increased assists in defecation, vomiting or child birth.
Relaxation: the dome returns to the former position, reduces the volume to the thoracic cavity, resulting in expiration.
The Mediastinum Concept all of organs b
etween the left and right mediastinal pleurae is called mediastinum. It extends from the sternum in front to the vertebral column behind, and from the thoracic inlet above to the diaphragm below.
Subdivisions of mediastinum
Superior mediastinum Inferior mediastinum
Anterior mediastinum Middle mediastinum Posterior mediastinum
Left side of mediastnum
Root of lung
Pericardium
Phrenic n. & pericardiacophrenic a.
Left vagus n.
Left recurrent n. Thoracic aorta
Sympathetic trunk
Greater splanchnic n
Aortic arch
Thoracic ductLeft subclavian a.
Esophagus
Right side of mediastnum
Root of lung
Pericardium
Superior vena cava
Phrenic n. & pericardiacophrenic a.
Left vagus n.
Azygos v.
Sympathetic trunk
Esophagus
Arch of azygos v.
Trachea
Inferior vena cava
Superior mediastinum Locating - from inlet of thora
x to plane extending from level of sternal angle anteriorly to lower border of T4 vertebra posterioly
Contents Superficial layer
Thymus Three veins
Left brachiocephelic v. Right brachiocephelic v. Superior vena cava
Middle layer Aotic arch and its three br
anches Phrenic n. Vagus n.
Posterior layer Trachea Esophagus Thoracic duct
Relations of aortic arch
Anteriorly and to the left - pleura, lung phrenic n., pericardiacophrenic vessels and vagus n.
Posteriorly and to the right -trachea, esophagus, left recurrent n., thoracic duct, deep cardiac plexus
Superiorly - its three branches, left brachiocephalic v. and thymus
Inferiorly - pulmonary a., arterial ligament, left recurrent n., left principal bronchus and superficial cardiac plexus
Triangule of ductus arteriosus Bounded by phrenic n., left vagus n.
and left pulmonary a. Contents - arterial ligament , left re
current n. and superficial cardiac plexuses
Inferior mediastinum
Anterior mediastinum Location - posterior to body of
sternum and attached costal cartilages, anterior to heart and pericardium
Contents - fat, remnants of thymus gland, anterior mediastinal lymph nodes
Middle mediastinum Location - between anterio
r mediastinum and posterior mediastinum
Contents: hart and pericardium, beginning or termination of great vessels, phrenic nerves, pericardiacophrenic vessels , lymph nodes,
Posterior mediastinum Location - posterior to heart an
d pericardium, anterior to vertebrae T5 - T12
Contents: esophagus, vagus n., thoracic aorta, azygos system of veins, thoracic duct, thoracic sympathetic trunk, posterior mediastinal lymph nodes
Relations of esophagus
Anteriorly - trachea, bifurcation of trachea, left principal branchus, left recurrent n., right pulmonary a., anterior esophageal plexus, pericardium, left atrium, diaphragm
Posteriorly - posterior esophageal plexus, thoracic aorta, thoracic duct, azygos v., hemiazygos v.,accessory hemiazygos v., right posterior intercostal v.
Left - left common carotid a., left subclavian a., aortic arch, thoracic aorta, superior part of thoracic duct
Right - arch of azygos v.
Relations of thoracic aorta
Anteriorly - left root of lung, pericardium and esophagus
Posterior - hemiazygos v., accessory hemiazygos v.,
Right - azygos v. and thoracic duct
Left - mediastinal pleura
Thoracic duct Begins in front of L1 as a dilated sac, the
cisterna chyli, which formed by joining of left and right lumbar trunks and intestinal trunk
Enter thoracic cavity by passing through the aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein
Travels upward, veering to the left at the level of T5
At the roof of the neck, it turns laterally and arches forwards and descends to enter the left venous angle
Just before termination, it receives the left jugular, subclavian and bronchomediastinal trunks
Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb
Right lymphatic duct Formed by union of right jugular, subcl
avian, and bronchomediastinal trunks Ends by entering the right venous angl
e Receives lymph from right half of head,
neck, thorax and right upper limb
Mediastinal spaces
Retrosternal space - lies beween sternum and endothoracic fascia
Pretracheal space - lies within superior mediastinum, between trachea, bifurcation of trachea and aortic arch
Retroesophagus space - lies within superior mediastinum, beween esophagus and endothoracic fascia
Thoracic aorta Continuation of aortic arch at lower border of T4 Courses downward on left side of, then in front of
vertebral column Passes through aortic hiatus of diaphragm at level
of T12 vertebra to enter abdominal cavity Main branches
Parietal branches Nine pairs posterior intercostals arteries One pair subcostal artery For lower nine intercostals spaces and upp
er part of abdominal wall; superior phrenic arteries supply the superior surface of the diaphragm.
Visceral branches Bronchial branches: one or two for each lu
ng Esophageal branches Pericardial branches