What is the origin and course of the musculocutaneous nerve?

The musculocutaneous nerve originates from the lateral cord of the brachial plexus (C5–C7 roots) in the axilla. It travels downward and laterally, piercing the coracobrachialis muscle, then runs between the biceps brachii and brachialis muscles before emerging near the elbow as the lateral cutaneous nerve of the forearm.

Which muscles does the musculocutaneous nerve innervate?

It provides motor innervation to three muscles in the anterior arm: biceps brachii, coracobrachialis, and brachialis. These muscles are involved in forearm flexion and supination.

What sensory function does the musculocutaneous nerve have?

The nerve gives rise to the lateral cutaneous nerve of the forearm, which supplies sensory innervation to the skin over the lateral and anterior aspects of the forearm.

What are the clinical signs of a musculocutaneous nerve injury?

Injury can lead to weakness in forearm flexion and supination, loss of the biceps tendon reflex, and sensory deficits, such as numbness, along the lateral forearm.

How does the musculocutaneous nerve relate to the brachial plexus?

It is a direct branch from the lateral cord of the brachial plexus, specifically derived from the C5–C7 spinal nerve roots, making it a key component of upper limb innervation.

What is the role of the musculocutaneous nerve in elbow joint function?

It provides an articular branch to the elbow joint via its innervation of the brachialis muscle, contributing to proprioception and joint stability.

Musculocutaneous Nerve – Course, Branches & Injury