The document discusses the biomechanics of the elbow complex, which includes the elbow joint and proximal and distal radioulnar joints. It describes the bones that make up the elbow joint, including the humerus, ulna, and radius. The elbow functions as a modified hinge joint, allowing flexion and extension in the sagittal plane. The proximal and distal radioulnar joints allow forearm rotation. Ligaments like the ulnar collateral and radial collateral provide joint stability. Common injuries include elbow dislocations and lateral/medial epicondylitis.