The elbow joint contains three major parts: humerus, radius bone, and ulna. The humerus trochlea, humerus capitulum, the ulna, radius head, cartilage, muscles, ligaments and tendons - together they form the elbow joint.
The elbow joint is a hinge joint, so it only moves towards one direction. The elbow joint has two ligaments: the ulnar collateral ligament and the radial collateral ligament. These ligaments and the the surrounding muscles are used to provide strength and support.
Articular cartilage covers the bone ends, allowing the elbow bones to move easily. Biceps and brachialis are important, as these muscles help to move and flex the elbow.