It is synovial, uniaxial and hinge variety of joint. Lower end of the humerus, upper end of the radius and the upper end of the ulna participate in its formation. Capitulum articulates with the head of the radius and the trochlea with the trochlear notch of the ulnar. Medial flange of the trochlea projects lower down more than the lateral flange. This creates an angle between the long axis of the arm and the long axis of the forearm called the carrying angle. The joint has capsular, ulnar collateral and the radial collateral ligaments. Joint cavity has three pads of fats namely in the radial, coronoid and the olecronan. In normal extension of the elbow two epicondyles of the humerus and the tip of the olecronan are in one line. When the elbow is flexed these three points form an equilateral triangle. In dislocation of the elbow this relation is disturbed due to shift of the olecronan process. However in supra-condyler fracture there is no distortion of the equilateral triangle.