Neurology Lab 6 - Module 2 -Orbit - Muscles: Page 2 of 5

Ocular muscles - continued

Remove the frontal and parietal bones to expose the superior surface of the orbit.

Add the eyeball.

Using the Rotate tool, examine the orientation of the eye in the orbit.

Is the eyeball positioned in the orbit to allow us to look straight ahead?

Yes

	How do the muscles of the orbit keep the eye aligned?
Most of the muscle mass is located medially and therefore work together to maintain eyeball orientation.

An additional muscle is necessary to allow full movement of the eye. Add the levator palpebrae superioris.

NOTE: The levator palpebrae superioris is not highlighted in this view of the cadaver.

Using the Highlight tool, highlight this muscle and watch the sagital section to see how it is oriented with respect to the superior rectus muscle.

	Why is this muscle an important part of eye movements?
It lifts the eyelid in a superior direction when the eyeball is elevated. Otherwise you would just see the back of the eye lid.