Extraocular Motilities

Question 1

What is the purpose of the EOM test?

Answer 1

• To look for restriction of movement, such as paresis or paralysis
• To evaluate the bony orbit after trauma
• Evaluate CN III, IV, and VI
• Evaluate fixation abilities of the pt

Paresis- Partial paralysis. Muscle weakened.
Paralysis- Loss of muscle function.

Question 2

Physiological H (pursuits) checks how many cardinal positions of gaze?

Answer 2

9

In each position, one of the yoked pairs of muscles is working

Question 3

Hering’s Law of equal innervation

Answer 3

Both members of a yoke pair receive equal innervation.

Question 4

Which muscle is yoke with:

1. Right medial rectus
2. Right lateral rectus
3. Right superior rectus
4. Right inferior oblique
5. Right inferior rectus
6. Right superior oblique

Answer 4

1. Left lateral rectus
2. Left medial rectus
3. Left inferior oblique
4. Left superior rectus
5. Left superior oblique
6. Left inferior rectus

Question 5

How to test EOMs if the patient has prism in his/her glasses

Answer 5

Perform EOM with Rx on. Be aware of limitations created by the spectacles, such as double vision when doing pursuits. But you want the patient to be able to see.

Question 6

Complete third nerve palsy

Answer 6

CN III innervates many muscles of the eye (All except LR and SO), controls pupillary construction, and helps keep lids up when eyes are open.

If nerve palsy occurs, patient will have ptosis, a blown pupil, and a down and outward gaze.
(LR pulls eye lateral and SO pulls eye down)

Referral needed.

Question 7

Complete sixth nerve palsy

Answer 7

Abducens nerve palsy. CN VI controls the lateral rectus, therefore, the medial rectus is in charge and will pull the eye medially when the patient is in “Central gaze.”

Referral needed.