Anatomy of the elbow

The elbow complex is made up of three joints:

1- The humeroulnar joint, which allows flexion and extension. It is an inclined quasi “hinge” that allows movement only in one plane (flexion-extension to around 140°). The olecranon is a hook-like structure that sits in a deep valley (the distal humerus). The humeroulnar joint is flanked by powerful ligaments, making it very stable.
2- The humeroradial, or radiocapitellar, joint, which allows flexion-extension and pivoting of the radius, which turns nearly 180° when the forearm is externally rotated (pronation and supination).
3- The proximal radioulnar joint.

Four main groups of tendons attach at the elbow:

1- The elbow flexors (brachialis on the ulna and distal biceps on the radial tuberosity).
2- The elbow extensor, i.e., the triceps, which inserts at the back, on the olecranon.
3-  The lateral epicondyle muscles, which insert on the lateral side of the distal humerus and allow extension of the wrist and fingers as well as supination (external rotation).
 4- The medial epicondyle muscles, which insert on the medial side of the distal humerus and allow flexion of the wrist and fingers as well as pronation (internal rotation).

Important nerves pass across the joint and travel to the hand (median, radial and ulnar nerves), making any surgical procedure very tricky, especially in the elbow crease area.

“Despite its limited space, the elbow comprises many delicate anatomical structures. Elective elbow surgery is increasingly performed by elbow specialists.”