Skull Complete Slides 2013

Preview:

Citation preview

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 1/53

The Skull (I):jjjj

Cranial Vault & Base

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 2/53

Skull

The sup. part of axial sk., that:

1. Covers & protect the brain

2. Provides facial sk. (shape of face)

Skull = 22 bones:

1. Bones of braincase

2. Facial bones

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 3/53

Bones of Braincase (8 bones)

Frontal

(1)

Parietal

(2)

Occipital

(1)

Temporal

(2)

Sphenoid

(1)

Ethmoid

(1)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 4/53

Facial Bones (14 bones)

Zygomatic (2)

Maxilla (2)

Nasal (2)

Lacrimal (2) Vomer (1)

Palatine (2)

Inferior Conchae (2)

Mandible (1)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 5/53

The Cranium

Cranium = Skull – Mandible

Divided into:

Braincase (neurocranium)

Upper facial sk. ( face bones,

viscerocranium)

* Usually most physicians refer to the

whole skull as cranium

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 6/53

Bones of braincase

1. Cranial Vault:

- forms the roof & sides of brain box

- (Frontal, Parietal, Squamous of occipital, squamous of 

temporal & greater wing of sphenoid)

- fibrous joints (sutures)

2. Cranial Base:

- forms the floor of brain box

- (orbital frontal, ethmoid, sphenoid, petrous temporal & basilar

occipit)

- cartilaginous joints centrally (why?)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 7/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 8/53

Cranial Vault (Calvaria)

Oval in shape & broadens post.

Made up of:

which bones? 

Cran. Vault bones are:

Diploic Bones

Extensions:

Supraorbital margins (ant.) 

 

Sup. Nuchal line & EOP (post.) 

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 9/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 10/53

Cranial Vault

3 sutures:

1. Coronal suture

which bones? 

2. Sagittal suture

which bones? 

3. Lambdoid suturewhich bones? 

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 11/53

4 points

1. Bregma:

intersection of sagittal & coronalsutures

2. Vertex:

sup. topmost point of the cranium

3. Lambda:

intersection of sagittal & lambdoid

sutures

4. Pterion: (G, pteron: wing)

-sup. to midpoint of zyg. arch

-indicated by H-shaped sutures

-very dangerous area ( why?  ) 

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 12/53

Cranial Base (Base of The Skull)

The floor of brain box

2 surfaces

I. Internal surface (endocranial):

3 fossae (depressions)

Ant., Middle, & Post.

II. External surface:

inf. aspect of the skull

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 13/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 14/53

Anterior Cranial Fossa

Made of:

1.Orbital plates of frontal bone:

anterolateral

frontal crest & foramen cecum

2.Lesser wing of sphenoidposteriorly, sharp boundary

3.Cribriform plate of ethmoid

central, roof of nasal cavity

perforated for transmission of olf. Ns.

*crista galli: (L, cock’s comb) 

median projection from crib. Ethmoid that 

 provides attachment site for meninges 

Ant. Fossa = 2 foramina ?

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 15/53

Middle Cranial Fossa

Butterfly-shaped:

Centrally:

sella turcica (sphenoid body)

Laterally:

2 depressed parts

Extensions:

Post. wing of sphenoid

 

Sup. Border of petrous temporal

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 16/53

Sella Turcica

Composed of 1. Tuberculum sellae:

Ant. elevation

horn of the saddle

2. Hypophysial fossa:pituitary fossa

3. Dorsum sellae:

post. bony elevation

back of the saddle

Surrounded by:

clinoid processes (bed post)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 17/53

Sphenoid Bone

Middle of skull base (keystone)

Consist of:

Body:

sphenoid air sinuses

Greater Wing

floor of ??

Lesser Wing

post. part of ??Pterygoid processes:

(legs)

pterygoid plates

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 18/53

Foramina in Middle Cranial Fossa

1. Optic canal:lesser wing

optic n.

2. Sup. Orbital fissure:

between lesser & greater

wings

communicates?

3. Foramen Rotundum: (round)greater wing

post. to medial end of 

sup. Orbital fissure

V2

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 19/53

4. Foramen ovale: (oval)

greater wing,

posterolat. to rotundum

V3

5. Foramen Spinosum:

greater wingposterolat. To ovale

middle meningeal a.

6. Foramen Lacerum:

between sphenoid & temporal

coverd by cartilage in life

artificate foramen after death

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 20/53

Posterior Cranial Fossa

The largest & deepest fossa

Made of:

post. surface of petrous temporal

occipital bone

(basilar & condylar)

very small portion of 

sphenoid body

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 21/53

Centrally:

Clivus

F. Magnum

Int. Occipital Crest

IOP

2 broad grooves

(linear depressions)

Transverse V. Sinuses

Sigmoid V. Sinuses

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 22/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 23/53

Foramina in Post. Fossa

1. Foramen Magnum

occipital bone (basilar)

M. oblongata & meninges,

V.a., spinal XI

2. Jugular Foramen:

between temporal & occipital

Int. Jugular V. & ???

3. Hypoglossal Canal:

anterolat. Wall of F. magnumXII

4. Int. Acoustic Meatus:

ant. to jugular, VII & VIII

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 24/53

External Surface of Cranial Base

(Inf. Aspect of Skull)

Facial Sk. (viscerocranial) Part:

Alveolar Processes of Maxillae

Palatine Processes of Maxillae*

Horizontal Plates of Palatine Bone*

Vomer

*Hard Palate*

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 25/53

Braincase (neurocranial) Bones:

Sphenoid

pterygoid plates & greater wing

Temporal Bone:

mandibular fossa

styloid & mastoid processes

S-M foramen & carotid canal

Occipital Bone:which parts?

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 26/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 27/53

Skull (II):

Facial Skeleton

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 28/53

Facial Bones (14 bones)

Zygomatic (2)

Maxilla (2)

Nasal (2)

Lacrimal (2) Vomer (1)

Palatine (2)

Inferior Conchae (2)

Mandible (1)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 29/53

Divided into

Forehead

frontal

Orbital cavities:

pyramidal, 4 walls

Nasal cavity

Jaws:

maxillae & mandible

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 30/53

Forehead

Made by: forntal bone

*Nasion:

intersection of frontal & nasal

bones

*Metopic suture (frontal):

in immature skulls

in median plane

usually fuses in early childhood

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 31/53

Orbital Cavity

Pyramidal in shape, 4 walls?

Contains:

eyeball & lacrimal apparatus

2 fissures (inside):

Sup. Orbital fissure

between?, communicates?

Inf. orbital fissure

between?, communicates?

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 32/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 33/53

Nasal Cavity

Located between:

Ant. Cranial Fossa

&

Oral Cavity

Nasal Septum:

Rt. & Lf.

1. perp. Plate of ethmoid

2. vomer

Nasal Conchae:

lateral wall

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 34/53

Maxilla

Body & 4 Processes

Body:

pyramidal

hollow inside (max. sinus)

2 foramina:

Infraorbital F.

ant. wall, infraorbital n.

Incisive Foramen:

between palatine processes

post. to central incisors

incisive n. (nasopalatine n.)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 35/53

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 36/53

Maxillary Processes

Zygomatic:

projects lat.,ant. zyg. Arch

Frontal:

sup.,

lat. to nasal bones

Alveolar:

inf.,

contains upper teeth

Palatine:

post.,

ant. 2/3 of hard palate

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 37/53

Largest & strongest facial bone

Only movable skull bone

Horizontal part:

Body

Vertical Parts:

Rami (ramus)

Jxn.:

Angle

Mandible

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 38/53

Body:

mental foramen

alveolar process

Ramus:

mandibular notchcoronoid process

condylar process:

head & neck

lingula & mand. foramen

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 39/53

Paranasal Sinuses

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 40/53

Paranasal Sinuses

Air-containing spaces within cranial bones

Lined with respiratory epithelium in life (which type?)

Suggested Fxn.’s: 

1. reduce skull weight

2. voice modification (sinusitis?)

3. insulation effect:prevent heat loss from nasal cavity

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 41/53

1. Maxillary Sinuses

maxillary bones, pyramidal

middle meatus

2. Frontal Sinuses

frontal bone, above the orbit

middle meatus

3. Sphenoid sinuses

sphenoid body

both sinuses separated by

septum

sphenoethmoidal recess

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 42/53

4. Ethomidal air cells:

ant. & middle:

middle meatus

Post.:

sup. Meatus

5. Mastoid air cells:temporal

middle ear

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 43/53

Skull (III):

Skull Fractures

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 44/53

Fractures of Calvaria

• Fracture Resistance:

- Convexity of the skull

- Diploid bone

Fracture Types:1. Linear fractures (most frequent )

2. Depressed fractures (thin areas)

3. Comminuted fractures (strong blow, several pieces)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 45/53

Pterion Fractures

Pterion is a dangerous region of the skull:

1. Point of weakness

H-shape suture

2. Ant. branch of middle meningeal artery

(Epidural hemorrhage)

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 46/53

Cranial Base Fractures

Anterior Cranial Fossa Fractures:

damage to crib. Plate of ethmoid

 Nasal bleeding “epistaxis” 

Tearing of meninges

CSF leakage into nose

“cerebrospinal rhinorrhea” 

Fract. Of orbital plate of frontal bone

Bleeding into orbital cavity

“exophthalmos” 

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 47/53

Middle Cranial Fossa Fractures:

Common fractures Because it is the ?? part of the base of skull due to ???

CSF leakeage through EAM

inj. To 3rd  – 6th cranial nerves

Posterior Cranial Fossa Fractures:

Bleeding into post. Vertb. Muscles

Inj. To 9th  – 11th cranial nerves

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 48/53

Facial Fractures

3 Types (planes of weakness)

Le Fort I

transmaxillary

Le Fort IIpyramidal, subzygomatic

(max., lacrimal, nasal)

Le Fort III

suprazygomatic, craniofacial

whole upper facial sk. detached

Usually complicated e soft tissue damage (hemorrhage, edema, pain) 

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 49/53

Nasal Bone Fracture

Most frequent facial fracture

Most commonly in Boxer’s 

Complications:

fracture of orbital margin

injury to frontal or ethmoidal

sinuses

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 50/53

Mandibular Fractures

1. Condylar Fractures:

most common + body

blow to chin when mouth is open

2. Body Fractures:

most common + condylar

usually near canine region:

-root length

-max. covexity

blow to the side of the jaw

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 51/53

3. Fractures of the Angle:

2nd most common

2directions:

downwards backwards

dislocation

downwards forwards

4. Coronoid Process Fracture:

least common (1-2%)

temporalis attachment

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 52/53

Mandibular Fractures 2nd most frequent after Nasal fractures

Notes:

1. If you see a fracture or dislocation in the mandible, look for another 

 fracture or dislocation

2. Panoramic x-ray is the best to diagnose mandibular fractures

3. Look for cortical margin & mandibular canal discontinuity 

7/29/2019 Skull Complete Slides 2013

http://slidepdf.com/reader/full/skull-complete-slides-2013 53/53

Panoramic X-ray

Recommended