muskulocutaneous

Musculocutaneous, in anatomical and clinical usage, refers to structures related to both muscle and skin. It most often denotes the musculocutaneous nerve, a nerve of the upper limb arising from the brachial plexus with fibers from the C5 to C7 nerve roots. It supplies motor innervation to the anterior compartment of the arm and provides sensory input to the forearm.

The nerve originates from the lateral cord of the brachial plexus and travels laterally between the biceps brachii and brachialis, eventually piercing the coracobrachialis. It gives motor branches to the coracobrachialis, biceps brachii, and brachialis, enabling flexion of the elbow and, in coordination with the forearm, forearm supination. Distally, it becomes the lateral antebrachial cutaneous nerve, which provides sensation to the lateral aspect of the forearm.

Functionally, the musculocutaneous nerve is essential for elbow flexion and for forearm supination when the elbow is flexed; its sensory component supplies the lateral forearm region.

Clinical significance includes injury or compression of the nerve, leading to weakness or loss of elbow flexion and forearm supination, with decreased sensation on the lateral forearm. Causes include trauma to the upper arm, repetitive strain, compression, or iatrogenic injury during shoulder or chest procedures. Diagnosis is based on clinical examination supported by nerve conduction studies and electromyography; imaging may be used to identify compression or entrapment. Management ranges from conservative therapy and physical rehabilitation to surgical intervention for compression release or nerve repair in cases of severe injury. Prognosis depends on the injury type and timing of treatment, with potential for partial to full recovery in many cases.