Figure 2.

 A schematic representation of the enthesis organs associated with the medial and lateral epicondyles based on fig 1. The elbow is thus drawn in coronal (frontal) section with the humerus located proximally and the radius and ulna distally. Both the articular cartilages of the elbow (AC1) and superior radioulnar (AC2) joints are visible. (A) The lateral epicondyle. The lateral collateral ligament (L) fuses with the annular ligament (AL), which in turn wraps around the radial head at the position of the arrow. The common extensor tendon (T) lies immediately lateral to the collateral ligament and the entheses of these two structures are fused. The single fused enthesis serves to dissipate stress concentration between tendon and ligament at the bony interface and stress is further reduced by the contact between annular ligament and radial head (arrow). Consequently, the enthesis organ comprises the tendon, collateral ligament, annular ligament, and the adjacent circumference of the radial head. (B) The medial epicondyle. The medial collateral ligament (M) fuses with the tendon (T) of the common flexor origin at its enthesis and the former presses against the articular cartilage on the edge of the humerus at the position of the arrow. The enthesis organ thus consists of the tendon, collateral ligament, and a part of the humeral articular cartilage.