This slide depicts the functions of the extraocular muscles as viewed by the
right eyeball. So we need to quickly orient you to the lateral and medial
aspects of the eye that we see right in through here. This will be the medial aspect
of the right eye. This will be the lateral aspect of the right eye. So now, let’s look
at the functions of the muscles that attach to the eyeball. First, we’re going to look
at muscles elevating and moving the eye in or out. First up is the internal oblique.
This will move the eye up and out or laterally. Next is the superior rectus depicted here.
It will also move the eyeball up but it’s going to move the eyeball in or medially.
Next, we have two muscles that depress and move the eyeball out or in. First up
is the superior oblique. The superior oblique will move the eye down or depress it
and will move the eye outwards or laterally. Next, we have the inferior rectus.
It too will depress or move the eye downwards but it will move the eye medially
or inward. This slide represents two muscles, one of which will adduct the eyeball
and the other will abduct the eyeball. First up out of this pair will be the medial
rectus. As we can see here, the eye has been moved inward medially or adducted,
so all three of those words describe the same movement. The other muscle
is the lateral rectus. This muscle movement is shown here. In this case,
the eyeball has been moved laterally and this is termed abduction. This is an MRI
of the orbit. In this particular section, axial section, we can identify very clearly
two recti muscles. Here’s the nose. Here is the right eyeball. Again, the left side
of an MRI scan will be the patient’s right side. So the right eyeball was shown here.
This would be the medial rectus on the medial side of the orbit. Then over on the
lateral side, we can see the lateral rectus. That concludes our presentation.