Triceps Muscle Anatomy
Arm Muscle Anatomy

The Triceps are the muscles on the back of the upper arm, and below is just a brief overview of the anatomy of this arm muscle.

"Tri" + "cep" literally, means "3 heads", and there are 3 parts to this one muscle-- a long head, a lateral head, and a medial head.

Each muscle starts at a different point on the body, but all of the muscles attach to the same place on the elbow.


The long head originates (starts) on the infraglenoid tubercle of the scapula which means that is crosses the shoulder joint.

The lateral head starts on the posterior part of the humerus. It is situated towards the top outside (lateral) part of the humerus.

The medial head starts on the posterior part of the humerus also. But it is situated on the lower inside (medial) part of the humerus.


All three heads insert (finish) on to the olecranon process of the ulna. The olecranon process is the big protrusion of the ulna that makes up the elbow.


All three parts of the tricep muscle will extend/ straighten the elbow.

The long head is the only part that crosses over the shoulder joint, so the long head can actually assist at pulling the shoulder backwards (shoulder extension).

Nerve Supply:

All parts of the muscle are innervated by the radial nerve.

Exercises for the Triceps

Obviously, any exercise that focuses on straightening the elbow will work all heads of this muscle. And there are many good isolation exercises and compound exercises.

Examples of isolation exercises are things like kick backs, push downs, or overhead extensions. But, remember that all three heads will also work during compound exercises like push ups, the bench press, or the military press.

Choose a variety of exercises, and mix up your workout to keep it fun and challenging.

Yours in health,
Dr. Charles PT/PT

Learn all Best Triceps Exercises

Return to the Main Arm Muscle Anatomy Page

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