Blood supply to head, eye movements, ear

Question 1

Arterial distribution

Answer 1

Ant circulation - fast
Ant cerebral and middle cerebral

Post circulation - post cerebral, brainstem (dizziness/coma)

Question 2

Extra-ocular muscles

Answer 2

SR, IR, medial rectus, inf oblique (CN III)

Sup oblique (CN IV)

LR (CN VI)

Question 3

Orbit nerves

Answer 3

CN VI - lacrimal, frontal, nasociliary (ethmoidal, infratrochlear)

CN III - sup and inf divisons

CN IV and VI

Question 4

Ext ear

Answer 4

Ceruminous glands - secrete cerumen, wax is cerumen and sebum and skin cells
Skin on tympanic membrane - constantly migrate radially away

Question 5

Middle ear

Answer 5

Sensory innervation - CN IX
Connects to mastoid antrum and pharynx

2 muscles - sapeeis (CN VIII) and tensor tympani (CN VIII)

2 nerves - chord tympani (CN VII) and tympanic nerve (CN IX)

Question 6

Inner ear

Answer 6

Bony labyrinth - perilymph
Membranous labyrinth - endolymph

Semi- circular ducts - rotational acceleration
Utricle - horizontal acceleration
Saccule - vertical acceleration

Question 7

Facial nerve

Answer 7

Internal acoustic meatus
Turns 90 deg post (geniculate ganglion) and 90 deg inferiorly
Stylomastod foramen

Bells palsy

Enters parotid gland and has 5 divisions
Forehead sparing in UMN lesions