What is the primary function of the axillary nerve?

The primary function of the axillary nerve is the innervation of the deltoid muscle. This nerve is crucial for the abduction and stabilization of the shoulder, allowing the arm to be lifted away from the body. The axillary nerve also provides sensory innervation to the skin overlying the deltoid muscle, contributing to proprioception and sensitivity in that area.

In the context of motor function, the deltoid muscle is essential for various movements of the arm, and damage to the axillary nerve can significantly affect shoulder function, making this nerve key in both athletic performance and daily activities that require arm mobility and strength.