MODULE 9
FUNCTIONAL RELATIONSHIPS of the EXTRAOCULAR MUSCLES
- - - You have already considered the action of the extraocular muscles in Gross Anatomy and will do so in your neurological diagnosis sessions. Blumenfeld handles this very well on Pages 530-535; Haines makes the same points on Pages 454-5 and in Figure 28-1. We will stick to the following brief statements:
----- - - - 1) The action of any given extraocular muscle is variable, and depends upon the position of the eyeball when the muscle contracts.
----- - - - 2) To test the medial rectus muscle, ask the patient to look at your finger, and move your finger in such a way that the eye must turn inward.
----- - - - 3) To test the lateral rectus muscle, move your finger in such a way that the eye must turn outward.
To test the remaining four muscles do the following:
------ - - 4) Move your target finger laterally, so the eye looks away from the midline by about 23 degrees (OK, roughly that amount); then move it upward to test the superior rectus or downward to test the inferior rectus.
----- - - - 5) Then move your target finger medially, so the eye turns in by about 39 degrees (again, roughly); then move it upward to test the inferior oblique (it pulls the bottom of the eye forward) or downward to test the superior oblique (it pulls the top of the eye forward).
- - - Now, look at some slides:
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