Scalp, Brain and Cranial Nerves

Question 2

what are the 5 layers of the scalp

Answer 2

S = skin
C = dense connective tissue
A = epicranial aponeurosis
L = loose connective tissue
P = pericranium

Question 3

epicranial aponeurosis

Answer 3

tendon and muscle of occipitofrontalis
prevents wounds from gaping open, when compromised sutures will be needed to close

Question 4

loose connective tissue

Answer 4

loose tissue that allows free movement of outer layers over underlying calvaria
has spaces susceptible to distension with fluid or infection spread [eyelids/root of nose]

Question 5

blood supply to the face

Answer 5

majority from ECA, some ICA
facial, buccal, mental, infraorbital, transverse facial

ICA - zygomaticofacial, zygomaticotemporal

Question 6

venous drainage of the face

Answer 6

facial vein drains most to IJV
transverse facial vein drains some upper face

Question 7

danger triangle of the face

Answer 7

no valves in external facial veins, blood flows in both directions, veins deep to this triangle drain into the cavernous sinus
skin infections in this area may spread as intracranial infections

Question 8

lymphatic drainage of the face

Answer 8

pre-auricular + parotid = near ear, from eyelids, lateral cheek and nose

submandibular = follows facial artery, from medial ordbit, npse, cheek, lip, lateral lower lip

submental = inferior chin, medial lower lip and chin

Question 9

nerve supply of face

Answer 9

trigeminal
V1 - upper, supraorbital and supratrochlear
V2 - zygomaticotemporal
V3 - auriculotemporal

cervical 2/3
greater occipital and lesser occipital
third occipital
great auricular

Question 10

lobes of the brain

Answer 10

frontal
parietal
occipital
temporal

Question 11

circle of Willis

Answer 11

circle anastomotic loop
allows for equalisaiton of blood flow between 2 hemispheres of the brain
essential in case artery becomes compromised as blood supply is maintained via collateral circulation

Question 12

name the 12 cranial nerves

Answer 12

olfactory
optic
oculomotor
trochlear
trigeminal
abducens
facial
vestibulocochlear
glossopharyngeal
vagus
accessory
hypoglossal

Question 13

12 cranial nerves function

Answer 13

olfactory - sense of smell
optic - vision
oculomotor - motor eye movements
trochlear - eye movements
trigeminal - sensation to head, motor to muscle of mastication
abducens - eye movements
facial - motor to muscles of facial expression
vestibulocochlear - hearing and balance
glossopharyngeal - sensation to posterior 1/3 tongue and oropharynx
vagus - general sensation to pharynx, larynx
spinal accessory - SCM and trapexius motor
hypoglossal - motor to tongue muscles

Question 14

where do the 12 cranial nerves exit the skull

Answer 14

1 - cribriform plate forimina
2 - optic canal
3 - superior orbital fissure
4 - superior orbital fissure
5 - superior orbital fissure, foramen rotundum, foramen ovale
6 - superior orbital fissure
7 - internal acoustic meatus
8 - internal acoustic meatus
9 - jugular foramen
10 - jugular foramen
11 - jugular foramen
12 - hypoglossal canal

Question 15

facial nerve supplies

Answer 15

general - parasympathetic to lacrimal gland, nasal, oral, submandibular and sublingual
special sensory - taste for anterior 2/3 tongue
motor - MoM, stylohyoid, posterior belly of digastric

Question 16

facial nerve course

Answer 16

exits via internal acoustic meatus with CN VIII
[at risk of compression here]

exits stylomastoid foramen to give off
- posterior auricular and digastric [pdiagstric and stylohyoid inervation]

main nerve then enters parotid, 5 main branches

Question 17

5 branches of facial nerve

Answer 17

temporal - occipitofrontalis, orbicularis occuli
zygomatic - orbicularis oculi, upper lip
buccal - buccinator, lip muscles
marginal mandibular - lower lip muscles
cervical - platysma

bilateral half upper facial sparing