The muscles on the front of the upper arm consist of three
muscles- biceps brachii muscle, brachialis muscle, and coracobrachialis muscle.
The biceps brachii muscle is a strong supinator of the forearm; it flexes the
elbow joint, and the long head of the biceps stabilizes the shoulder joint. The
brachialis muscle is the primary flexor of the elbow joint. The
coracobrachialis functions as flexion and adduction of the shoulder. The
musculocutaneous nerve arises from the lateral cord of the brachial plexus. It
is the primary nerve supply to these three muscles. It is the primary nerve
supply of the muscles of the anterior compartment of the upper arm. It supplies
sensation to the lateral half of the forearm.
The triceps muscle is another muscle of the upper arm, but it is located
on the back of the upper arm. The triceps muscle functions as the powerful
extensor of the elbow joint. The muscle has three heads: long head, lateral
head, medial head. It is innervated by the radial nerve from the posterior cord
of the brachial plexus.
