Elbow Joint

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.

Proximal Radio-Ulnar Joint

The proximal (superior) radio-ulnar joint is a pivot type of synovial joint that allows movement of the head of the radius on the ulna.

Articulation of Proximal Radio-Ulnar Joint

The head of the radius articulates with the radial notch of the ulna. The radial head is held in position by the anular ligament of the radius.

Ligaments of Proximal Radio-Ulnar Joint

The strong anular ligament, attached to the ulna anterior and posterior to its radial notch, surrounds the articulating bony surfaces and forms a collar that, with the radial notch, creates a ring that completely encircles the head of the radius. The deep surface of the anular ligament is lined with synovial membrane, which continues distally as a sacciform recess of the proximal radio-ulnar joint on the neck of the radius. This arrangement allows the radius to rotate within the anular ligament without binding, stretching, or tearing the synovial membrane.