Neurocranium I Flashcards
dura mater
1) outer periosteal
2) inner meningeal layer
arachnoid mater
1) outer mesothelial layer is adherent to the dura mater
2) inner trabecular layer forms leptomeningeal bridges to pia mate
pia mater
1) contiguous with arachnoid trabeculae
2) intimal layer adherent to surface of brain
epidural space
1) between dura mater and skull
2) in the cranium, it is only a potential space
subdural space
1) between dura mater and arachnoid mater
2) only a potential space
subarachnoid space
1) bridged by arachnoid trabeculae
2) blood vessels and CSF
epidural hematoma
1) bleeding into the potential space between bone and dura mater
2) traumatic injury of the middle meningeal artery due to skull fracture
3) compression of the brain can be fatal
subdural hematoma
1) bleeding into the potential space between the dura bater and the arachnoid
2) typically caused by violent shaking or jarring
3) small bridging veins are torn
- cerebral veins between surface of the vein and the dural sinuses
4) small children and the elderly are susceptible
falx cerebri
1) two-layered projection of meningeal dura along the median plane of the cranial vault, separating the left and right cerebral hemispheres
2) anterior attachment: crista galli
3) posterior attachment: internal occipital protuberance
falx cerebelli
1) two-layered projection of meningeal dura along the median plane of the cranial vault, separating the left and right cerebral hemispheres of cerebellum
2) runs along the internal occipital crest
tentorium cerebelli
1) two layers of the falx cerebri separate from each other to project laterally
2) extend bilaterally from falx cerebri to the superior petrosal sulcus
3) free anterior edges form the tentorial incisura
diaphragma sellae
1) dural membrane extending from the anterior clinoid processes to the posterior clinoid processes
2) covers the hypophyseal fossa (sella turcica)
3) pituitary stalk (hypophyseal infundibulum) passes through a hiatus while the gland remains beneath
dura mater innervation
1) supratentorial innervation
- trigeminal nerve CN V
- sensory
2) infratentorial innervation
- vagus nerve (CNX)
- cervical spinal nerve C1-3
meningeal blood supply
1) is embedded in the dura mater
-middle meningeal artery
- branch of maxillary artery from the external carotid artery
2) the arachnoid mater is avascular
- gets everything from CSF
- but the arachnoid space has vessels
3) the pia matter gets blood from arteries that pass over the surface of the cerebrum
- from internal carotid
meningeal blood supply accessory arteries
1) accessory meningeal artery
2) occipital artery
3) vertebral artery
4) ascending pharyngeal artery
5) anterior ethmoidal artery
6) posterior ethmoidal artery
* no need to memorize except for middle meningeal artery
cerebral blood supply
1) internal carotid
- 70% of blood supply
2) vertebral arteries
- 30% of blood supply
cricle of willis
1) vertebral arteries => basilar artery => posterior cerebral arteries
2) internal carotid
=> middle cerebral arteries
=> anterior cerebral arteries
3) posterior communicating arteries
- connect posterior cerebral with internal carotid
4) anterior communicating artery (singular) connect anterior cerebral arteries
venous drainage
1) blood from the cerebral cortex and meninges drains to surface veins that empty into dural venous sinuses
2) dural sinuses =/= paranasal sinuses (air-filled)
superior sagittal sinus
1) formed by the separation of the meningeal dura from the periosteal dura
2) arachnoid villi (granulations when calcified)
- filled with CSF that return to the blood stream
3) drains blood from the superior portion of the brain
4) lateral projections of this sinus form lacunae whihc contain additional arachnoid villi
superior sagittal sinus location
1) superior margin of the falx cerebri
2) receive blood from the outer surface of the brain
inferior sagittal sinus
1) blood from medial surfaces of cerebral hemispheres
straight sinus role
1) shunts blood from inferior sagittal sinus to the confluens of the sinuses
straight sinus
1) receives great cerebral vein
- great vein of galen
2) drains blood from brainstem
transverse sinuses
1) receives blood from the superior sagittal and the straight sinussign
sigmoid sinuses
1) receive blood from transverse sinuses
2) drains into internal jugular vein
cavernous sinuses
1) lie on either side of sella turcica
2) receive blood from
- sphenoparietal sinus
- superior Opthalmic vein
- interior ophthalmic vein
- pterygoid venous plexus
3) drain into superior and inferior petrosal sinuses
contents of cavernous sinus
1) oculomotor nerve CNIII
2) trochlear nerve CNIV
3) abducens nerve CNVI
4) opthalmic nerve CN V1
5) portion of the maxillary nerve CN V2
6) internal carotid artery
dural venous sinuses and CSF
1) superior sagittal sinus receives CSF from subarachnoid space
2) CSF flows into the sinus via arachnoid villi
choroid plexus
1) CSF is ultrafiltrate of blood produced by choroid plexus of the cerebral ventricular system
2) 300 mL per day
3) highly convoluted fenestrated capillaries surrounded by ependyma
4) lies within the lumen of the ventricular system
-fluid filled space derived from embryological neural tube
5) subarachnoid space is continuous with the ventricles (cavities) within the brain
6) ventricular system is continuous with the central canal of the spinal cord
ventricles
1) lateral ventricles drain the interventricular foramen (of monro) into the third ventricle
2) third ventricle connects to fourth ventricle via the cerebral aqueduct
3) from fourth ventricle, CSF can
- continue into central canal of spinal cord
- exit into subarachnoid space via:
a) lateral foramina (of luschka)
b) median foramen (of magendie)
embryology of ventricular system
1) ventricular system is neural tube
2) lateral walls of the forebrain expand and protrude from both sides of the neural tube
3) lateral ventricle…????
cranial nerves
1) just memorize them all
olfactory nerve CNI
1) cribriform plate of the ethmoid bone
2) special sensory afferent fibers (SSA)
3) not visible in cadaver
4) project from nasal mucosa to olfactory bulb
- olfactory bulb and olfactory tract are part of the brain
optic nerve CNII
1) nerve and retina are outgrowth of the brain
2) special sensory afferent fibers (SSA)
3) optic canal is where it passes through
4) left visual field maps to right side of the brain (and vice versa)
5) fibers from the nasal retina cross the midline at the optic chiasm
oculomotor nerve CNIII
1) GSE
- extraocular muscles of the eye
2 ) also supplies the parasympathetic innervation of eye
- GVE
3) passes through the cavernous sinus and the superior orbital fissure
trochlear nerve CN IV
1) controls the superior oblique muscle of the eye (GSE)
2) passes through the cavernous sinus and superior orbital fissure
3) only cranial nerve to originate from the posterior aspect of the brainstem
trigeminal nerve CNV
1) GSA to the face, meninges, eye, nasal cavity, oral cavity, and tongue
2) single sensory ganglion with 3 divisions
- ophthalmic (passes through cavernous sinus and superior orbital fissure)
- maxillary (foramen rotundum)
- mandibular (foramen ovale)
—
1) GSE to
- muscles of mastication
- anterior belly of digastric
- mylohyoid muscle
- tensor veli palatini
- tensor tympani
2) motor innervation runs with V3
abducens nerve CNVI
1) GSE to the lateral rectus muscle of the eye
2) runs freely through the cavernous sinus
3) passes through the superior orbital fissure
facial nerve CN VII
1) GSE to
- muscles of facial expression
- posterior belly of the digastric m
- stylohyoid muscle
2) GVE (parasympathetic)
- submandibular, sublingual, and lacrimal glands
3) SSA from anterior 2/3 of tongue
4) GSA to oropharynx and small region around the ear
5) exits through the internal acoustic meatus
- travels through the facial canal in the temporal bone
- exits the skull through stylomastoid foramen
vestibulocochlear nerve CN VIII
1) SSA to the cochlea and vestibular system
2) exits the neurocranium via internal acoustic meatus
glossopharyngeal nerve CN IX
1) GSA to the pharynx and the posterior 1/3 of tongue
2) SSA fibers for the posterior 1/3 of the tongue
3) exits from jugular foramen
vagus nerve CNX
1) GVE to heart, lungs, and digestive tract
2) GVA to the abdominal and thoracic viscera
3) GSE to the muscles of pharynx and larynx
4) exits through jugular foramen
spinal accessory nerve XI
1) cranial component and a spinal component
2) spinal component enters from foramen magnum
3) GSE to trapezius and SCM
hypoglossal nerve XII
1) somatic motor innervation to tongue muscles
2) exit the neurocranium via the hypoglossal canal
what to know for the quiz
1) how it gets out of skull
2) the name of the nerve and number
