Which nerve innervates the biceps brachii?

The biceps brachii is primarily innervated by the musculocutaneous nerve. This nerve originates from the brachial plexus, specifically from the lateral cord, and is responsible for providing motor innervation to the biceps brachii muscle, allowing for actions such as flexion of the elbow and supination of the forearm.

Understanding the role of the musculocutaneous nerve in the upper limb's muscle function highlights its significance in both everyday movements and physical activities that involve lifting or curling motions. This particular nerve also contributes sensory information from the lateral aspect of the forearm, showcasing the multifaceted role of nerve innervation in both motor and sensory pathways.

The other nerves mentioned have distinct functions and are responsible for innervating different muscle groups, which is why they do not innervate the biceps brachii. The radial and ulnar nerves control other muscles in the arm and hand, while the median nerve mainly innervates muscles of the forearm and some hand muscles. Understanding the specific functions of nerves in relation to the muscles they innervate is crucial in anatomy and physiology, especially for clinical applications.