The Motility Exam
Title: The Motility Exam
Author: Eric Peterson, MSIV, BS
Keywords/Main Subjects: Ocular Motility Exam;
Description of Image:
The ocular motility exam can be a simple yet profoundly important part of the ophthalmic exam. Six extraocular muscles act to move the eye up/down, left/right and intort/excyclotort. These six muscles control the eye in a complex combination of agonist and antagonist cooperation. Interestingly, the extraocular muscles have the densest ratio of motor neurons to muscle fibers of any muscle in the body, thus facilitating the tremendously fine motor control and impeccable alignment of the eyes.
The actions of the eye muscles are most easily assessed by utilizing the H motility pattern as seen in Figure 1. These six cardinal positions along with primary gaze are particularly useful when assessing ocular motility because each cardinal position is primarily obtained by the action of one muscle. For example, elevation of the eye from primary gaze is accomplished by actions of both the superior rectus and the inferior oblique. However, elevation of the abducted eye is primarily accomplished by the superior rectus, while elevation of the adducted eye is primarily accomplished by the inferior oblique. Similarly, depression in abduction isolates the inferior rectus while depression in adduction isolates the superior oblique. Figure 2 demonstrates each of the nine positions with captions describing the muscle(s) being used to obtain that particular position.
When testing motility, assess the eye alignment in primary gaze (consider using the Hirschberg test) and then have the patient move the eyes in an “H” pattern, as shown in Figure 1. Using your finger, a light or a toy, trace an “H” pattern in front of the patient while instructing them to hold their head still. Be sure to alternate between observing the left and right eye in each gaze during the exam.
Faculty Approval by: Griffin Jardine
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