Lateral collateral ligament complex of the elbow

The lateral collateral ligament complex of the elbow is composed by four primary structures: 

• Lateral ulnar collateral ligament (LUCL): originates at the lateral epicondyle of the humerus and partially blends in with the annular ligament as it travels distally to insert on the supinator crest of the ulna.

• Radial collateral ligament proper (RCL): a fan-shaped ligament that originates at the lateral epicondyle of the humerus and runs longitudinally underneath the common extensor tendon blending with the anterior annular ligament

• Accessory lateral collateral ligament (ALCL): one-third of individuals have an accessory lateral collateral ligament, which runs from the annular ligament to the supinator crest of the ulna.

• Annular ligament (AL) 

The radial collateral ligament proper (RCL) of the elbow is a part of the lateral collateral ligament complex of the elbow. It is a fan-shaped ligament that originates at the lateral epicondyle of the humerus and runs longitudinally underneath the common extensor tendon blending with the anterior annular ligament. 

It is analogous to the “Radial collateral ligament of elbow (Ligamentum collaterale radiale cubiti)”  listed in the Terminologia Anatomica.