Which nerves innervate the brachialis?

The brachialis muscle is primarily innervated by the musculocutaneous nerve, which is responsible for supplying motor function to this muscle. Additionally, there is minor innervation from the radial nerve, specifically to the part of the muscle that lies underneath the musculocutaneous nerve. This dual innervation allows the brachialis to perform its primary function in elbow flexion efficiently.

The musculocutaneous nerve arises from the lateral cord of the brachial plexus, primarily supplying flexor muscles in the anterior compartment of the arm, including the brachialis. Meanwhile, the radial nerve contributes to its innervation, particularly to ensure proper motor control around the elbow joint. This combination reflects the muscle's significance in elbow movement, which is critical for various arm functions.