Scalp, Cranial Cavity, Meninges, Dural/Cavernous Sinus Flashcards
what are the layers of the scalp?
skin
connective tissue: dense, contains blood vessels
aponeurosis: galea aponeurotica connects the two bellies of the occipito-frontalis m.
loose connective tissue
periosteum: thin collagenous layer adhered to the skull
what are the nn. of the scalp that are anterior to the ear?
supraorbital and supratrochlear n. (br. of V1)
zygomaticotemporal n. (br. of V2)
auriculotemporal n. (br. of V3)
what are the nn. of the scalp that are around the ear?
great auricular nn. (C2, C3)
what are the nn. of the scalp that are behind the ear?
greater and lesser occipital nn. (C2)
what is the blood supply to the anterior scalp?
internal carotid aa. —-> br. of ophthalmic a. —-> supraorbital a. & supratrochlear a.
what is the blood supply to the posterior scalp?
external carotid a. —-> br. of external carotid a. —-> superficial temporal a. & posterior auricular a. & occipital a.
what are emissary veins?
communication with the scalp and venous structures of brain
allows for toxic substances to get to the brian
what are diploic veins?
veins that reside entirely in the brain
what are the meninges?
dura mater, arachnoid layer, pia
what are the two layers of the dura mater?
endosteal layer
meningeal layer
what is the endosteal layer?
follows contours of the skull, fuses with foramen magnum
what is the meningeal layer?
separates from the upper layer at various points form dural sinuses sheath of cranial nerve II sclera of the eye compartments that separate brain regions dura on spinal cord
what are the meningeal compartments
falx cerebri
tentorium cerebelli
falx cerebelli
diaphragma sellae
what is the blood supply to the dura mater?
middle meningeal a.
anterior meningeal a.
posterior meningeal a.
where is the middle meningeal a. from?
external carotid a. —-> maxillary a. —-> middle meningeal a.
where is the anterior meningeal a. from?
internal carotid a. —-> ophthalmic a. —-> anterior meningeal a.
where is the posterior meningeal a. from?
external carotid a. —->occipital a. —-> posterior meningeal a.
subclavian a. —-> vertebral a. —->posterior meningeal a.
what is the arachnoid layer?
delicate membrane with arachnoid granulations and sub-arachnoid space
what are arachnoid granulations
collection of villi
diverticula of arachnoid membrane
project into dural sinuses to return CSF to venous drainage
what is in the subarachnoid space?
CSF
major blood vessels (circle of Willis)
where does the pia adhere to and how?
closely adheres to brain
connected to brain parenchyme by glial endfeet
what does the pia form?
forms choroid plexus of ventricles which forms CSF
what is an epidural hematoma?
vascular trauma where blood trapped btwn dura and inner table of skull. confined. causes lens shaped clot. caused by tearing of arterial vessels (middle meningeal esp b/c lat aspect of skull is thinner than ant and pos)
what does an epidural cause clinically?
LOC with lucid intervals
what is an subdural hematoma?
vascular trauma where blood trapped btwn dura and arachnoid. more diffuse than epidural. caused by venous structures tearing
what does a subdural hematoma cause clinically and where is this seen?
may resolve over time
seen in shaken baby syndrome
HA, one side paralysis, lethargy
what is a subarachnoid hemorrhage?
rupture of intracranial vessels with blood flowing along sulci of brain.
small a. ruptures. bloodied CSF
blood clot may prevent flow of CSF
what does a subarachnoid hemorrhage cause clinically?
worst HA of life, stiff neck, LOC
blood clot may prevent flow of CSF and result in hydrocephalus=fluid exerts pressure=not good
