Orbit

Question 1

Lacrimal duct opening

Answer 1

Into superior conjunctival fornix laterally

Question 2

PS innervation of lacrimal gland

Answer 2

From superior salivatory (lacrimal) nucleus, CN VII, pterygopalatine ganglion, V2 and V1 branches

Question 3

Removal of lacrimal fluid

Answer 3

Lacrimal puncta
Lacrimal canaliculi
Lacrimal sac
Nasolacrimal duct
Inferior nasal meatus

Question 4

Ophthalmic a from

Answer 4

Internal carotid

Question 5

Ophthalmic a branches

Answer 5

Posterior ciliary aa

Central retinal a

Question 6

Ophthalmic vv to

Answer 6

Drain to cavernous sinus

Anastomoses with vv of face and scalp

Question 7

Levator palpebral superioris

Answer 7

Elevates eyelid

Question 8

Visual axis and orbital axis

Answer 8

VA straight ahead

OA 23degrees lateral

Question 9

Superior rectus actions

Answer 9

Elevates (adducts, intorts)

Question 10

Inferior rectus actions

Answer 10

Depresses (adducts, extorts)

Question 11

Superior oblique origin, actions

Answer 11

Origin from apex
Functional origin from trochlea
Depresses, abducts, intorts

Question 12

Inferior oblique origin, actions

Answer 12

Origin from anterior, inferior, medial corner of orbit

Elevates, abducts, extorts

Question 13

Eye smooth mm innervation

Answer 13

Preganglionic PS axons from Edinger-Westphal nucleus in CN III
Synapse in ciliary ganglion
To pupillary sphincter and ciliary m

Question 14

Ophthalmic division

Answer 14

Lacrimal n
Frontal n (supratrochlear, supraorbital)
Nasociliary n (various branches including eye somatosensory)

Question 15

Superior orbital fissure

Answer 15

CN III, IV, V1, VI travel through

Question 16

Inferior orbital fissure

Answer 16

CN V2 travel through

Question 17

CN II course

Answer 17

Enters orbit through optic canal

An extension of CNS with meninges

Question 18

Medial or lateral strabismus

Answer 18

Deviation to medial or lateral side

Question 19

CN III origin

Answer 19

Oculomotor nucleus (LMN) and Edinger-Westphal nucleus (PS preganglionic neutron cell bodies)
Rostral midbrain

Question 20

CN IV origin

Answer 20

Trochlear nucleus

Caudal midbrain

Question 21

CN VI origin

Answer 21

Abducens nucleus

Caudal pons

Question 22

LMNs of extraocular mm

Answer 22

Almost all LMNs innervate ipsilateral mm

Question 23

Trochlear nucleus

Answer 23

Trochlear nucleus
Forms contralateral trochlear n
To contralateral superior oblique

Question 24

Oculomotor nucleus

Answer 24

Oculomotor nucleus LMNs for superior rectus
To contralateral oculomotor n
To contralateral superior rectus

Question 25

Horizontal gaze centre

Answer 25

In pons
PPRF (paramedian pontine reticular formation)
Coordinate horizontal conjugate movements
MLF (medial longitudinal fasciculus) connects abducens nucleus internuclear neurons and oculomotor nucleus LMNs

Question 26

Vertical gaze centre

Answer 26

In midbrain
riMLF (rostral interstitial nucleus of medial longitudinal fasciculus)
Coordinate vertical conjugate movements

Question 27

Vestibulooculear reflex (VOR)

Answer 27

Fixation on an object while head moving

3-4 neuron reflex

Question 28

Saccades (scanning)

Answer 28

Rapid change of eye direction

Involve eye fields of cerebral cortex

Question 29

Smooth pursuit

Answer 29

Follow moving object

Involves extrastriate visual cortex, eye fields, pontine nuclei, flocculus of cerebellum