Where do the triceps start and end?

The triceps brachii muscle starts at three points: the long head originates from the infraglenoid tubercle of the scapula, the lateral head arises from the posterior surface of the humerus, and the medial head comes from the posterior surface of the humerus, below the radial groove. All three heads converge to form a single tendon that inserts at the olecranon process of the ulna in the elbow. This anatomical structure allows the triceps to extend the forearm at the elbow joint.