Musculus brachialis
Origin: Proximocaudal surface of humerus. Insertion: Proximomedial surface of radius. Innervation: Musculocutaneous nerve; lateral parts of muscle by radial nerve in half of horses. Function: Flexor of elbow joint. Long fibers allow considerable shortening during contraction.
Origin: Caudolateral surface of the proximal humeral shaft (musculospiral groove)
Insertion: Medial surface of the proximal radius and ulna
Action: Flexes the elbow joint
Innervation: Musculocutaneous nerve (C6-C7)
Overuse from repeated intense elbow flexion (racehorses, eventers). Can be difficult to differentiate from bicipital bursitis.
Overuse from repeated intense elbow flexion (racehorses, eventers). Can be difficult to differentiate from bicipital bursitis. Signs include: Forelimb lameness with shortened swing phase; pain on forced elbow flexion; reluctance to flex the elbow; may resist farrier holding the limb up.
See the Brachialis on our interactive 3D horse model. Open 3D Model