Which nerve is responsible for innervating the deltoid and teres minor muscles?

The axillary nerve is responsible for innervating the deltoid and teres minor muscles, which are crucial for shoulder movement. The deltoid muscle, a large triangular muscle located on the shoulder, is primarily responsible for arm abduction, flexion, and extension. The teres minor, a smaller muscle located just above the teres major, plays a role in external rotation of the arm and assists with shoulder stabilization.

The axillary nerve arises from the posterior cord of the brachial plexus, specifically from the C5 and C6 nerve roots. It travels around the humerus and provides motor innervation to these two muscles, enabling them to function effectively during various shoulder movements. Additionally, the axillary nerve also innervates the skin over the lateral aspect of the shoulder, providing sensory feedback.

The other nerves listed do not innervate the deltoid or teres minor. For example, the median nerve primarily innervates flexor muscles of the forearm and some hand muscles, the radial nerve is involved in the innervation of the triceps brachii and extensor muscles of the forearm, and the ulnar nerve primarily supplies the flexor carpi ulnaris and most intrinsic hand