The Elbow

The tendon of the biceps is attached to the rough posterior area of the radial tuberosity.
The latter is a few cm distal of the joint line.

In full supination the radial tuberosity faces anteriorly. (1)
During a pronation movement, the tuberosity turns medially and the insertion of the biceps
moves between the lateral aspect of the ulna and the radial tuberosity. (2)
In full pronation position of the elbow, the radial tuberosity faces backwards.
The tendon can then be palpated between the radial and the ulnar shaft,
a few cm distal of the joint line. (3)