Skull Flashcards
What are the two main subdivisions of the skull?
Cranium and mandible
What are the 5 external views (normas) of the skull?
1) frontalis
2) laterialis
3) occipitalis
4) verticalis
5) basalis
What are the 2 internal surface views of the skull?
Inner surface of skull cap
cranial cavity
What are the 4 bones of the norma verticalis?
frontal
2 parietal
occipital
What are the sutures of of the normal veticalis?
coronal
sagittal
lamboid
What is bregma?
Meeting of coronal and sagittal sutures
site of anterior fontenelle
should close 1 finger each month until 2 years
What is lambda?
Meeting of the lambdoid and sagittal sutures
site of posterior fontenelle
should close at 3 months
What is a fontenelle?
Soft spot of skull
What are the features of the inner surface skull cap?
4 bones: frontal, 2 parietal, occipital
sagittal sulcus (boney groove for superior sagittal sinus)
granular foveolae (depressions from arachnoid granulations)
What is the norma occipitalis?
formed from occipital bone, mastoid part of temporal bones and part of parietal bones
has external occipital protubverance and crest for trapezius and ligamentum nuchae
nuchal lines for suboccipital muscles and deep back muscles
What is normal frontalis?
frontal bone 2 nasal bones bony orbit 2 zygomatic bones 2 maxillary bones
What is supraorbital foramen?
carries supraorbital nerve and vessels
What is superior orbital fissure?
carries CN III, IV, V1, VI
What is optic canal?
carries optic nerve and opthalimic artery
what is inferior orbital fissure?
carries maxillary nerve, infraorbital vessels
what is infraorbital foramen?
carries infraorbital nerve and vessels
what is mental foramen?
in the mandible and carries mental nerve and vessels
What is normal lateralis?
formed from temporal bone zygomatic bone greater wing of sphenoid bone maxillary bone frontal parietal occipital
what is the temporal fossa?
superiorly: temporal line
inferiorly: zygomatic arch
Floor: pterion
What is the pterion?
H shaped structure
formed from 4 bones
frontal, parietal, temporal, greater wing of sphenoid
4 cm above zygomatic arch
on top of middle meningeal artery
What causes an epidural hematoma?
Injury that ruptures the middle meningeal artery and its branches
it runs close to the bone/superficial/ prone to injury. near pterion
go to ER because the swelling can compress the motor area of the brain- contralateral hemiplasia
What is the zygomatic arch?
formed by temporal process of zygomatic bone and zygomatic process of temporal bone
What are the three processes of the zygomatic bone?
1) temporal
2) maxilla
3) frontal
What are the three fossas of the normal lateralis?
temporal
infratemporal
pterygopalatine (fissure between maxilla and pterygoid)
What are the three fossa of the cranial cavity?
anterior middle posterior
3 steps from low (posterior) to high (anterior)
What is the median projection of the cribriform of the ethmoid bone?
crista galli
separated from frontal crest by foramen caecum
What is the median projection from the posterior border of the lesser wing of sphenoid?
Anterior clinoid process
What is the optic canal?
located medial to the anterior clinoid process
carries optic nerve and ophthalimic artery
What is the optic chiasma?
connects both optic nerves
located in the optic groove (sulcus chiasmaticus)
Where can you see the lesser wing of the sphenoid?
From the inside only
What is the sella turcica?
middle of middle cranial fossa formed by body of sphenoid
behind the optic groove
pituitary gland with stalk connected to brain sits here
What could happen if you get a tumor near the caverna sinus?
near the caverna sinus there are many CNs going in lateral wall
might affect pitutary of nerve near by if there is a tumor
pituitary close to optic groove with optic chiasma with optic nerve so tumor could cause
BLINDNESS
What are the 3 parts of the sella turcica?
anterior slope (tuberculum sellae) median groove (hypophyseal fossa) posterior elevated part (dorsum sellae)
What does the superior orbital fissure transmit?
CN 3, 4, 5, 1, 6
inferior boundary formed by greater wing of sphenoid
What are the 3 foramina of the greater wing of sphenoid?
Formamen rotundum- maxillary neve V2
Foramen ovale- mandibular nerve V3
Foramen spinosum- middle meningeal artery
What are the 3 parts of trigeminal nerve?
1) V1 opthalmic- superior orbital
2) V2 maxillary- for rotundum
3) V3 mandibular- for ovale
where does the internal carotid pass?
goes through carotid canal with opening in cranial cavity= foramen laserum
No branches in the neck
caverna sinus - arterial blood in venus blood
What is the large hole in the middle floor of the posterior cranial fossa?
Foramen magnum
What is the basalar part of the occiptal bone that slopes upwards?
Clivus
What are the 3 important foramem of the posterior cranial fossa?
Internal auditory meatus- CN 7 and 8
Jugular- CN9, 10, 11
Hypoglassal canal- CN12
Which foramen is closest to the foramen magnum?
Hypoglossal canal
Jugular
Internal acoustic
What is the slope behind the foramen magnum?
Internal occipital crest
How does the brain drain?
Transverse sinus
sigmoid sinus
internal juglar
right atrium
What are the emissary veins to the face?
caverta sius
What is in the optic canal?
optic nerve and opthalmic artery
