Lecture 26: Eye and Orbit II

Question 1

5 cranial nerves in orbit

Answer 1

CN II, III, IV, V1, VI

Question 2

Optic nerve enters orbit via

Answer 2

Optic canal

Question 3

3 structures that pass through optic canal

Answer 3

Optic nerve
Internal ophthalmic artery
Internal ophthalmic vein

Question 4

Which muscle pulls the eye back into the orbit

Answer 4

Retractor bulbi

Question 5

7 extrinsic eye muscles

Answer 5

Dorsal, ventral, medial and lateral recti
Dorsal and ventral obliques
Retractor bulbs

Question 6

Parasympathetic branch of CN III

Answer 6

Short ciliary nerves

Question 7

Long ciliary nerve innervation

Answer 7

Sensory from cornea and sclera

Question 8

anterior and posterior ethmoidal nerves

Answer 8

Sensory from naval cavity

Question 9

Short ciliary nerves innervation

Answer 9

Parasympathetic to pupillary sphincter and ciliary muscle

Question 10

Pathway of CN III innervating ciliary ganglion

Answer 10

Preganglionic parasympathetic cell bodies in Edinburg Westphal nucleus (midbrain) —> CN III —> synapse at ciliary ganglion —> hitchhike on short ciliary nerves —> innervate pupillary sphincter and ciliary muscle

Question 11

Function of lateral rectus

Answer 11

Cornea looks laterally
Rotation laterally/abduction

Question 12

Which muscle causes nictitating membrane/3rd eyelid to partially cover eye

Answer 12

Retractor bulbs

Question 13

3 sensory branches of V1/ophthalmic nerve

Answer 13

Lacrimal
Frontal
Nasociliary

Question 14

Nasocilary nerve (from C1): innervation

Answer 14

Sensory from nasal cavity, cornea, sclera

Question 15

Frontal nerve (from V1) innervation

Answer 15

Sensory from skin of forehead and scalp

Question 16

Lacrimal nerve (from V1) innervation

Answer 16

Sensory from lacrimal gland, conjunctiva and upper eyelid

Question 17

2 branches of nasociliary (from from V1)

Answer 17

Long ciliary nerves
Anterior and posterior ethmoidal nerves

Question 18

Which nerve branch from V1 nasociliary gets sensory from cornea and sclera

Answer 18

Long ciliary nerves

Question 19

Which branch of nasociliary from V1 gets sensory from nasal cavity

Answer 19

Anterior and posterior ethmoidal nerves

Question 20

Which branch of oculomotor gets parasympathetic to pupillary sphincter and ciliary muscle

Answer 20

Short ciliary nerves

Question 21

Lacrimal gland innervation

Answer 21

Sensory from lacrimal nerve
Parasympathetic from pterygopalatine ganglion (CN VII)

Question 22

Sympathetic pathway to eye and head (3 features)

Answer 22

Site of synapse = cranial cervical ganglion
Internal carotid periarterial plexus = postganglionic sympathetics to dilator papillae and superior tarsal muscles
External carotid periarterial plexus = postganglionic sympathetics to face

Question 23

Visual pathway

Answer 23

Photoreceptors —> bipolar neurons —> retinal ganglion nucleus —> lateral geniculate nucleus of thalamus —> primary visual cortex/occipital lobe

Question 24

Where do 1/2 of optic axons cross the midline and are delivered to opposite side

Answer 24

Optic chiasm

Question 25

2 main visual fields in retina

Answer 25

Temporal Nasal

Question 26

Nasal vs temporal part of retinas: what happens to info

Answer 26

Nasal crosses to OTHER SIDE Temporal stay on same side

Question 27

What kind of info do optic tracts contain

Answer 27

Mixed info 1/2 from each side (due to nasal crossing in the middle)

Question 28

Direct light reflex

Answer 28

Pupil constricts in eye stimulated by light

Question 29

consensual light reflex: definition, importance

Answer 29

Pupil constricts in Contralateral eye (Even though light not shined in that eye) Demonstrates crossing of info at chias

Question 30

Edinger westphal nuclei and pretectal area are part of what brain region

Answer 30

Midbrain

Question 31

Primary visual cortex located in what lobe

Answer 31

Occipital

Question 32

Pupillary light reflex pathway

Answer 32

Optic nerve fibers synapse at pretectal areas —> pretectal nerve fibers synapse bilaterally at edinger westphal nuclei —> EW nerve fibers (preganglionic parasympathetic) synapse at ciliary ganglia —> postganglionic parasympathetic fibers in ciliary ganglia synapse on pupillary sphincter muscle and cause it to contract

Question 33

Pupillary dilation reflex process

Answer 33

Preganglionic sympathetic nerve fibers synapse in superior portion of sympathetic trunk —> postganglionics synapse on pupillary dilator muscle

Question 34

Short ciliary arteries are Anastamoses between

Answer 34

External and internal carotid arteries

Question 35

Main blood supply to orbital contents

Answer 35

Short ciliary arteries

Question 36

Internal ophthalmic artery goes through what hole

Answer 36

Optic canal

Question 37

Venous drainage of orbital contents

Answer 37

Brain —> cavernous sinus—> vertebral and internal jugular veins

Question 38

what nerve innervates retractor bulbs

Answer 38

CN VI

Question 39

Medial rectus vs lateral rectus function

Answer 39

Medial - adduct eye Lateral - abduct eye

Question 40

Dorsal vs ventral rectus function

Answer 40

Dorsal - adduct and elevate eye Ventral - adduct and depress eye

Question 41

Ventral vs dorsal oblique function

Answer 41

Ventral - abduct and elevate eye Dorsal - abduct and depress eye

Question 42

2 muscles that accomplish looking up

Answer 42

Dorsal rectus Ventral oblique

Question 43

2 muscles that accomplish looking down

Answer 43

Ventral rectus Dorsal oblique