ANATOMY

The elbow joint can both hinge and rotate to a limited degree. The bones of the joint are the humerus (upper arm), and the paired ulna and radius of the forearm. The bony tip of the elbow is the olecranon process of the ulna (popularly called the funny bone), and the inner aspect of the elbow is called the antecubital fossa.

To allow the hand to be turned palm up or palm down, the elbow joint must rotate as well as hinge. There is therefore a second joint at the end of the radius which is shaped like a smooth knob with a cup at the end. This allows movement between the radius and humerus to bend the elbow, but also to enclose the end of the humerus so the two can glide smoothly together allowing wrist rotation.

The main muscles powering movement of the elbow are the biceps, the triceps, the wrist extensors (attaching to the lateral epicondyle on the outer front of the elbow) and the wrist flexors (attaching to the medial epicondyle on the inner aspect of the elbow).

The elbow is also a complex crossroads for the three main nerves (radial, ulnar and median) connecting the shoulder to the hand, each passing through its own tunnel through the elbow. Repeated bending and twisting at the elbow also flexes the nerves and can commonly cause problems with pain, numbness and loss of strength or movement in the arm and hand.