The elbow joint connects
the bone of the upper arm, the humerus, with the two bones of the lower
arm, the radius and the ulna. Within the joint structure are three smaller
joints, created by the communication of the three separate bones. The humerus-ulna
joint and the humerus-radius joint contribute to the hinge-like motion
of the arm. The radius-ulna joint and the humerus-radius joint permit rotation
of the forearm and the palm-up, palm-down positioning of the hand.
