Brachialis Muscle

The brachialis muscle is a key muscle located in the upper arm, lying underneath the biceps brachii. It plays a crucial role in elbow flexion, which is the movement of bending the elbow.

Anatomy of the Brachialis Muscle

• Location: The brachialis is situated on the anterior (front) side of the humerus, deep to the biceps brachii.
• Origin: It originates from the lower half of the anterior surface of the humerus.
• Insertion: The muscle inserts into the coronoid process and tuberosity of the ulna.
• Innervation: The brachialis is primarily innervated by the musculocutaneous nerve (C5 and C6), though part of it may also receive innervation from the radial nerve.

Function

The primary function of the brachialis is to flex the elbow joint, pulling the forearm toward the upper arm. Unlike the biceps brachii, which also assists with supination (rotating the forearm), the brachialis is a pure elbow flexor and works regardless of whether the forearm is in a supinated or pronated position.

Clinical Relevance

• The brachialis muscle can be involved in conditions such as tendinitis or muscle strain, especially in activities that involve repetitive elbow flexion.
• Strengthening exercises targeting this muscle, such as reverse curls or hammer curls, can enhance overall arm strength and stability.

In summary, while often overshadowed by its more prominent neighbor, the biceps brachii, the brachialis is a powerful and essential muscle for elbow flexion, contributing significantly to arm movement and strength.