Cranial Nerve Skull Foramina Flashcards
cribriform plate
olfactory nerve bundles (CN I)
optic canal
Optic Nerve (CN II) Ophthalmic artery
superior orbital fissure
- Oculomotor Nerve (CN III)
- Trochlear N (CN IV)
- Trigeminal N, ophthalmic branch (CN V,1) : lacrimal, frontal, nasociliary branches
- Abducens N (CN VI)
- Superior ophthalmic vein
foramen rotundum
Trigeminal N., Maxillary branch (CN V,2)
foramen ovale
- Trigeminal N., Mandibular branch (CN V,3)
- Accessory meningeal artery
- lesser petrosal n (occasionally)
foramen spinosum
- middle meningeal a/v
- meningeal branch of mandibular n (CN V,3)
foramen lacerum
greater petrosal nerve crosses this space
carotid canal
- internal carotid artery
- internal carotid nerve plexus
internal acoustic meatus
- Facial N (CN VII)
- Vestibulocochlear N (CN V VIII)
- labyrinthine a
jugular foramen
- inferior petrosal venous sinus
- Glossopharyngeal N (CN IX)
- Vagus N (CN X)
- Accessory N (CN XI)
- sigmoid venous sinus
- posterior meningeal artery
hypoglossal canal
- Hypoglossal N (CN XII)
foramen magnum
- medulla oblongata
- meninges
- vertebral arteries
- meningeal branches of vertebral arteries
- spinal roots of accessory nerves
Which m. originates from the scaphoid fossa?
tensor veli palatini m.
Which n. runs through the petrotympanic fissure?
chorda tympani (br. of facial n.)
Which n. runs through the tympanic canaliculus?
tympanic n. (n. of Jacobson)
two parts of the dura mater
cranial dura
spinal dura
two layers of the cranial dura
periosteal outer layer
meningeal inner layer
(normally fused)
dural partitions
(reflections/infoldings of inner meningeal layer of dura mater)
- Falx Cerebri
- Falx Cerebelli
- Tentorium Cerebelli
- Diaphragma Sellae
Falx cerebri
separates cerebral hemispheres
Falx cerebelli
lies between the cerebellar hemispheres
Tentorium cerebelli
separates occipital lobes of cerebrum from the cerebellum
Diaphragma sellae
lies over the pituitary gland
dural venous sinuses
endothelial lined spaces formed between the meningeal and periosteal layers of the dura
important for draining blood into IJV
Emissary v. drain ______
while diploid v. drain ______
Emissary v. drain the SCALP
while diploid v. drain BONE
Path of superior sagittal sinus drainage
superior sagittal sinus –> confluence of sinuses –> R transverse sinus –> sigmoid sinus –> IJV
Path of inferior sagittal sinus drainage
inferior sagittal sinus –> confluence of sinuses –> L transverse sinus –> sigmoid sinus –> IJV
Path of occipital sinus drainage
occipital sinus –> confluence of sinuses –> L transverse sinus –> sigmoid sinus –> IJV
cavernous sinus drainage
either superior and inferior petrosal sinuses
superior petrosal sinus drainage
superior petrosal sinus –> transverse sinus –> sigmoid sinus –> IJV
inferior petrosal sinus drainage
inferior petrosal sinus –> sigmoid sinus –> IJV
cavernous sinuses
location, drain what?
paired dural venous sinuses.
found on either side of sella turcica.
drains the orbit, anterior aspect of brain, and sphenoparietal sinus.
content of cavernous sinuses
internal carotid a. w/ surrounding sympathetic plexus.
CN III, CN IV, CN V1, CN V2, and CN VI (embedded in lateral wall of the sinus)
cavernous sinus thrombosis signs/sx
pain conjunctival chemosis proptosis ptosis (CNIII) dilated pupil (CNIII) corneal reflex lost (CNV1) double vision facial sensory loss ophthalmoplegia (CNIII, CNIV, CNVI)
cavernous sinus thrombosis tx
- vigorous and early use of anticoagulants
- abx
- drainage and elimination of infection are essential.
innervation of dura on floor of anterior cranial fossa
meningeal branches of CN V (V1, V2, V3)
innervation of middle cranial fossa dura
meningeal branches of CN V (V2, V3)
innervation of tentorium cerebelli and posterior falx cerebri
tentorial branch of CN V1
innervation of anterior falx cerebri
anterior meningeal branches of ethmoidal n. (from nasociliary n.
Does the arachnoid mater contain vascular structures?
No, it’s avascular.
All cerebral a. and v. –> in subarachnoid space.
Arachnoid granulations
small projections to venous sinuses to drain CSF
Granular foveola
impressions on calvaria made by arachnoid granulations
Pia mater
vascular layer that is adherent to the brain surface, extends w/ cerebral sulk and cover gyri
arachnoid trabeculae
loosely connect arachnoid mater to pia mater
extracerebral bleeding
bleeding between bony calvarium and soft tissue of the brain
increases intracranial pressure
epidural hematoma
Usually due to ruptured middle meningeal a.
Blood contained between durra and inner table of the skull
Sx: initial lucid interval, HA, vomiting, clear fluid from nose/mouth, loss of consciousness 3-8 hr later
subdural hematoma
Blood between brain parenchyma and dural membranes
Elderly at risk (innate atrophy of cerebral cortex –> smaller brain vol –> inc space in subdural compartment –> inc stretch on bridging v. between skull and cerebral surface)
Concave lens shape
subarachnoid hematoma
bleeding between arachnoid and pia mater
causes: birth trauma, hypoxic ischemic injury, rupture of aneurysm
blood obstructs CSF reabsorption –> increased ICP w/ hydrocaphalus
tx: placement of ventricular drains and shunting system
(ventriculoperitoneal shunt)
which a. commonly exhibit Berry aneurysms
anterior cerebral a.
anterior communicating a.
circle of Willis
pt of cerebral circulation
- anterior cerebral a.
- anterior communicating a.
- internal carotid a. (L/R)
- posterior cerebral a. (L/R)
- posterior communicating a. (L/R)
paranasal sinuses
- mucosa-lined, air-filled spaces
- found in frontal/sphenoid/ethmoid/maxillary bones
- reduce weight of skull enhance resonance of voice warm and humidify inspired air absorb shock contrib to facial growth
sinusitis
inflammation of tissues lining the sinuses
causes: common cold, allergic rhinitis, nasal polyps, deviated septum
What accounts for up to 40% of maxillary sinusitis cases?
odotogenic sinusitis (infection spreads from teeth in upper jaw to maxillary sinus)
