Ulnar Collateral Ligament

The ulnar collateral ligament connects the medial epicondyle of the humerus to the coronoid process and the olecranon of the ulna.

It is composed of three ligamentous bundles: anterior (red), posterior (blue), and transverse (yellow).

In the throwing motion, the anterior bundle is under the most stress as the coronoid process of the ulna and the medial epicondyle of the humerus are pulled apart by vaglus torque.