Eye Movements

Question 1

Bones of the orbital socket (6)

Answer 1

Frontal bone
Ethmoid bone
Sphenoid bone
Zygomatic bone
Lacrimal bone
Maxillary bone

Question 2

How do orbital blow out fractures occur?

In which direction do they usually occur? Which bone is involved?

Where can stuff be trapped?

Answer 2

Fx of the orbital walls usually by indirect trauma.

Medially and inferiorly. Maxillary bone.

Trapped in maxillary sinus.

Question 3

What angle are the lateral walls of the orbit?

What does that make the optical axes (what angle)?

Answer 3

90 degrees.

45 degrees.

Medial walls are parallel basically.

Question 4

Movements of the eye around the vertical axis

Answer 4

Abduction and adduction

Question 5

Movements of the eye around the horizontal axis

Answer 5

Elevation or depression

Question 6

Movements of the eye around the AP (visual axis)

Answer 6

Intorsion or extorsion

Question 7

Which muscles does CN III innervate? (5)

Answer 7

Levator palpebrae superioris m.
Inferior oblique m.
Superior rectus m.
Inferior rectus m.
Medial rectus m.

Question 8

Which muscle does CN IV innervate?

Answer 8

Superior oblique m.

Question 9

Which muscle does CN VI innervate?

Answer 9

Lateral rectus m.

Question 10

Which muscles do extorsion?

Answer 10

IO m.

IR m.

Question 11

Which muscles do intorsion?

Answer 11

SO m.

SR m.

Question 12

Which direction do the muscles move the eye?
IO m.
LR m.
SO m.
SR m.
MR m.
IR m.

Answer 12

IO m - up and out
LR m. - out
SO m. - down and out
SR m. - up and in
MR m. - in
IR m. - down and in

Question 13

When lateral rectus m. abducts the eye, only which muscles can produce elevation/depression?

Answer 13

Only the superior and inferior rectus ms.

Question 14

When medial rectus m. adducts eye, only which muscles can produce elevation/depression?

Answer 14

Only the superior and inferior oblique ms.

Question 15

Nerves within the orbit (superior to the muscles) - 6

Answer 15

Supratrochlear n.
Supraorbital n.
Lacrimal n.
Frontal n.
Nasociliary n.
V1 (ophthalmic n.)

Question 16

Nerves of the orbit (deep to the muscles) - 7

Answer 16

Infratrochlear n.
Anterior ethmoidal n.
Posterior ethmoidal n.
Long ciliary n.
Short ciliary n.
Nasociliary n.
Sensory root of ciliary ganglion

Question 17

General sensory fibers from ciliary ganglion are within which nerve?

What stuctures does it innervate? (3)

Answer 17

Nasociliary n. (V1) –> long ciliary n.

Choroid, iris, cornea.

Question 18

Which nerve carries presynaptic PSNS fibers to the ciliary ganglion?

What nerve does it synapse with in the ciliary ganglion?

What structures does it act on? (2)

Answer 18

CN III.

Short ciliary n.

Sphincter pupillae m., ciliary m.

Question 19

What do post synpatic sympathetic ns. innervate? (3)

Answer 19

Dilator pupillae m.

Superior and inferior tarsal ms.

Question 20

Trochlear palsy

Answer 20

Head tilts away from affected side.

Double vision worse on downward glaze.

Question 21

Abducens palsy

Answer 21

Cannot look laterally w/ affected eye.

Question 22

Oculomotor palsy (3)

Answer 22

Down and out eye due to loss of innervation, except SO m. and LR m.

Complete ptosis due to loss of innervation to LPS m.

Pupil dilation due to loss of PSNS innervation to pupil.

Question 23

Pupillary light reflex (4)

Answer 23

1. Light sensed by CN II and synapses in pretectal nucleus.
2. Cells from pretectal nucleus will synapse in Edinger-Westphal nucleus.
3. Preganglionic PSNS neurons will travel w/ CN III and synapse in ciliary ganglion.
4. Postganglionic PSNS neurons synapse in pupillary constrictor m.

Question 24

Corneal reflex (3)

Answer 24

1. Receptors in cornea detect touch/irritation and travel in CN V and synapse in trigeminal sensory nucleus.
2. Cells from trigeminal nuclei project to facial nucleus.
3. Neuron in facial nerve will cause eye to blink.