Which nerve innervates the deltoid muscle?

The deltoid muscle is primarily innervated by the axillary nerve, which is crucial for its function in shoulder abduction, flexion, and extension. The axillary nerve branches from the posterior cord of the brachial plexus and specifically targets the deltoid muscle, as well as the teres minor. This innervation allows for effective movement of the arm, especially in raising it away from the body.

Understanding the roles of the various nerves is essential. The musculocutaneous nerve primarily innervates muscles in the anterior compartment of the arm, the median nerve is predominantly responsible for innervating forearm and hand muscles, and the radial nerve mainly innervates the extensor muscles of the arm and forearm. Each of these nerves serves different anatomical regions and muscle groups, but the direct connection to the deltoid muscle lies with the axillary nerve.