Scalp, Cranial Cavity, Meninges, Dural/Cavernous Sinus

Question 1

what are the layers of the scalp?

Answer 1

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

Question 2

what are the nn. of the scalp that are anterior to the ear?

Answer 2

supraorbital and supratrochlear n. (br. of V1)
zygomaticotemporal n. (br. of V2)
auriculotemporal n. (br. of V3)

Question 3

what are the nn. of the scalp that are around the ear?

Answer 3

great auricular nn. (C2, C3)

Question 4

what are the nn. of the scalp that are behind the ear?

Answer 4

greater and lesser occipital nn. (C2)

Question 5

what is the blood supply to the anterior scalp?

Answer 5

internal carotid aa. —-> br. of ophthalmic a. —-> supraorbital a. & supratrochlear a.

Question 6

what is the blood supply to the posterior scalp?

Answer 6

external carotid a. —-> br. of external carotid a. —-> superficial temporal a. & posterior auricular a. & occipital a.

Question 7

what are emissary veins?

Answer 7

communication with the scalp and venous structures of brain

allows for toxic substances to get to the brian

Question 8

what are diploic veins?

Answer 8

veins that reside entirely in the brain

Question 9

what are the meninges?

Answer 9

dura mater, arachnoid layer, pia

Question 10

what are the two layers of the dura mater?

Answer 10

endosteal layer

meningeal layer

Question 11

what is the endosteal layer?

Answer 11

follows contours of the skull, fuses with foramen magnum

Question 12

what is the meningeal layer?

Answer 12

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

Question 13

what are the meningeal compartments

Answer 13

falx cerebri
tentorium cerebelli
falx cerebelli
diaphragma sellae

Question 14

what is the blood supply to the dura mater?

Answer 14

middle meningeal a.
anterior meningeal a.
posterior meningeal a.

Question 15

where is the middle meningeal a. from?

Answer 15

external carotid a. —-> maxillary a. —-> middle meningeal a.

Question 16

where is the anterior meningeal a. from?

Answer 16

internal carotid a. —-> ophthalmic a. —-> anterior meningeal a.

Question 17

where is the posterior meningeal a. from?

Answer 17

external carotid a. —->occipital a. —-> posterior meningeal a.
subclavian a. —-> vertebral a. —->posterior meningeal a.

Question 18

what is the arachnoid layer?

Answer 18

delicate membrane with arachnoid granulations and sub-arachnoid space

Question 19

what are arachnoid granulations

Answer 19

collection of villi
diverticula of arachnoid membrane
project into dural sinuses to return CSF to venous drainage

Question 20

what is in the subarachnoid space?

Answer 20

CSF

major blood vessels (circle of Willis)

Question 21

where does the pia adhere to and how?

Answer 21

closely adheres to brain

connected to brain parenchyme by glial endfeet

Question 22

what does the pia form?

Answer 22

forms choroid plexus of ventricles which forms CSF

Question 23

what is an epidural hematoma?

Answer 23

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)

Question 24

what does an epidural cause clinically?

Answer 24

LOC with lucid intervals

Question 25

what is an subdural hematoma?

Answer 25

vascular trauma where blood trapped btwn dura and arachnoid. more diffuse than epidural. caused by venous structures tearing

Question 26

what does a subdural hematoma cause clinically and where is this seen?

Answer 26

may resolve over time
seen in shaken baby syndrome
HA, one side paralysis, lethargy

Question 27

what is a subarachnoid hemorrhage?

Answer 27

rupture of intracranial vessels with blood flowing along sulci of brain.
small a. ruptures. bloodied CSF
blood clot may prevent flow of CSF

Question 28

what does a subarachnoid hemorrhage cause clinically?

Answer 28

worst HA of life, stiff neck, LOC

blood clot may prevent flow of CSF and result in hydrocephalus=fluid exerts pressure=not good