Ligaments of Elbow Joint

The collateral ligaments of the elbow joint are strong triangular bands that are medial and lateral thickenings of the fibrous layer of the joint capsule. The lateral, fan-like radial collateral ligament extends from the lateral epicondyle of the humerus and blends distally with the anular ligament of the radius, which encircles and holds the head of the radius in the radial notch of the ulna, forming the proximal radio-ulnar joint and permitting pronation and supination of the forearm.

The medial, triangular ulnar collateral ligament extends from the medial epicondyle of the humerus to the coronoid process and olecranon of the ulna and consists of three bands:

(1) the anterior cord-like band is the strongest,

(2) the posterior fan-like band is the weakest, and

(3) the slender oblique band deepens the socket for the trochlea of the humerus.