How many muscle fibers does an average small motor unit typically innervate?

A small motor unit typically innervates 3 to 6 muscle fibers, which is a characteristic feature that allows for precise control of muscle movements. The smaller the motor unit, the greater the fine motor control that can be exercised over the muscles. This is particularly important in muscles that require delicate and intricate movements, such as those in the hands and face.

In contrast, larger motor units innervate hundreds to thousands of muscle fibers, which is more suited for gross motor functions where strength is prioritized over fine control. Therefore, the specific innervation of 3 to 6 muscle fibers in a small motor unit supports the body's ability to perform tasks that require high levels of dexterity and precision.