Skull and Cranial Cavity Flashcards
scalp layers
skin connective tissue aponeurotic layer loose connective tissue pericranium
scalp innervation
trigeminal nerve and spinal cutaneous nerves
bones of the skull
8 neurocranium
14 viscerocranium
neurocranium bones
occipital temporal x2 parietal x2 sphenoid ethmoid frontal
viscerocranium bones
nasal conchae x2 nasal bones x2 maxilla x2 palatine bones x2 zygomatic bones x2 lacrimal bones x2 vomer mandible
foramina
allow nerves and vessels to enter or leave the cranial cavity
important foramina
cribriform plate optic canal superior orbital fissure foramen rotundum foramen ovale foramen spinosum internal acoustic meatus stylomastoid foramen foramen lacerum jugular foramen hypoglossal canal foramen magnum
meninges layers
dura mater
arachnoid mater
pia mater
meninges roles
protection
support network for blood vessels
form fluid filled cavity to cushion and nourish brain
dura mater layers
endosteal layer - lines skull only
meningeal layer - around brain and spinal cord
space between = dural sinuses
dura mater nerve supply
trigeminal, vagus, C1-3 and sympathetic
dura mater blood supply
middle meningeal artery
meningeal layer of dura
arranged in folds/septa which divide the cranial cavity
folds restrict movement of the brain
falx cerebri
part of meningeal layer of dura mater
separates cerebral hemispheres
tentorium cerebelli
part of meningeal layer of dura mater
seperates cerebral hemispheres from cerebellar hemispheres
falx cerebelli
part of meningeal layer of dura mater
separates cerebellar hemispheres
dura mater clinical applictions
sensitive to stretching - anatomical basis for headache
damage to MMA can cause extradural haemotoma
tentorial herniation - caused by space occupying lesion, causing herniation of temporal lobe
arachnoid mater
thin, avascular layer between pia and dura
loosely applied layer with projections
subarachnoid space
contains CSF
arachnoid granulations
affect transfer of CSF to venous sinuses
extend into dura mater layer
pia mater
very delicate, vascular membrane
closely invests brain, following gyri/sulci
cerebral arteries enter carrying pia mater sheath
spinal cord meninges
meningeal layer of dura mater
arachnoid mater
pia mater
leptomeningitis
infection and inflammation in arachnoid and pia mater
infection may enter subarachnoid space and enter blood (septicaemia)
dural sinuses
sit between dural fold
drains blood and CSF from brain via cerebral veins
communicate with veins of skull and scalp
thick walled endothelium
no valves/smooth muscle
drain into internal jugular vein
dural sinuses examples (8)
inferior and superior sagittal sinuses sigmoid sinus superior and inferior petrosal sinuses straight sinus basilar sinus cavernous sinus sphenoparietal sinus transverse sinuses
brain blood supply
supplied by 2 main arteries: internal carotid and vertebral arteries
branches anastomose to form circle of willis
circle of willis
vertebral arteries unite to form basilar artery
basilar bifurcates to give off posterior cerebral and superior cerebellar arteries
internal carotid communicates with posterior cerebral artery by the posterior communicating artery
ICA gives off middle cerebral artery and anterior cerebral arteries
anterior cerebral communicate via anterior communicating artery
anterior cerebral artery
from internal carotid artery
supplies:
- medial and superior surfaces of the brain
- frontal pole
middle cerebral artery
from internal carotid artery
supplies:
- lateral surfaces
- temporal pole
posterior cerebral artery
from basilar artery
supplies:
- inferior surfaces
- occipital pole
stroke
caused by emoblism in cerebral artery
no anastomoses of cerebral arteries once inside brain
