branchesmusculocutaneous

Branches musculocutaneous refer to the muscular and cutaneous branches supplied by the musculocutaneous nerve, a component of the brachial plexus. The nerve arises from the lateral cord, carrying fibers from C5 to C7. It travels through the coracobrachialis muscle, often piercing it, and then descends between the biceps brachii and brachialis. Its muscular branches innervate the three main anterior arm muscles: coracobrachialis, biceps brachii, and brachialis. In addition to motor branches, the nerve often provides articular (sensory) branches to the shoulder and elbow joints.

The principal cutaneous continuation of the musculocutaneous nerve is the lateral antebrachial cutaneous nerve, which emerges distal to the biceps tendon and supplies sensation to the lateral aspect of the forearm. This sensory distribution is a key feature distinguishing musculocutaneous involvement from injuries to other upper limb nerves.

Anatomical variations are reported, including communications with the median nerve via the lateral root of the median nerve, or occasional alterations in the pattern or presence of certain branches. Such variations can affect the presentation of nerve injuries or nerve block procedures.

Clinical significance: injury or compression of the musculocutaneous nerve can weaken forearm flexion and supination due to loss of function in the biceps brachii and brachialis, with possible atrophy of the anterior arm muscles. Sensation to the lateral forearm may be diminished if the lateral antebrachial cutaneous branch is affected. The hand and wrist generally preserve function unless injury extends proximal to the lateral cutaneous branch.