A motor unit size of one axon per 10 extrafusal fibers might be expected in the ________ muscles.
A) elbow
B) wrist
C) eye
D) leg
E) forearm

Question

Quizplus · Accepted Answer

The eye muscles require precise movements and therefore have smaller motor units, typically consisting of one axon per 5-6 extrafusal muscle fibers. In contrast, larger muscles such as those in the leg or forearm may have motor units of one axon per 100 or more extrafusal muscle fibers. The elbow, wrist, and forearm muscles are not specific enough in terms of movement precision to require such a small motor unit size.

A Motor Unit Size of One Axon Per 10 Extrafusal