Elbow Joint Anatomy & Function Quiz

The humero-ulnar joint is classified as a hinge joint because it permits movement primarily in one plane. Anatomically, the trochlea of the humerus fits into the trochlear notch of the ulna, creating a stable articulation. This structure allows flexion and extension while restricting rotation, which is essential for controlled elbow movement.

The humero-radial joint connects the capitulum of the humerus with the head of the radius. This joint supports flexion and extension while also allowing the radial head to rotate during pronation and supination. Its dual function contributes to smooth forearm rotation combined with elbow motion.

The proximal radio-ulnar joint enables pronation and supination by allowing the radial head to rotate within the annular ligament. This rotation is essential for positioning the hand in functional activities such as gripping and tool use.

The distal radio-ulnar joint works in coordination with the proximal radio-ulnar joint to allow forearm rotation. Its articulation between the ulnar head and the ulnar notch of the radius ensures smooth pronation and supination.

The elbow joint capsule is thin and lined with synovial membrane to reduce friction. It encloses multiple articulations, allowing mobility while maintaining joint stability.

The posterior fibers of the medial collateral ligament extend from the medial humeral epicondyle to the olecranon. They resist valgus stress, particularly when the elbow is in extreme flexion.

Transverse fibers of the medial collateral ligament run between the olecranon and coronoid process. These fibers provide minimal stability but help maintain structural continuity of the ligament.

The lateral ulnar collateral ligament resists varus forces acting on the elbow. It is essential for posterolateral stability, preventing rotational instability during functional loading.

The annular and quadrate ligaments stabilize the radial head during rotation. They maintain joint congruency while allowing smooth pronation and supination without displacement.

The antebrachial fascia is a dense connective tissue that encloses the forearm. It separates muscle compartments and provides structural support, becoming thicker near the wrist for reinforcement.

The triceps brachii does not form part of the cubital fossa. The fossa primarily contains neurovascular structures and muscles like brachioradialis and pronator teres.

The origin of brachioradialis lies superior to the lateral epicondyle. This positioning allows the muscle to assist in elbow flexion from mid-pronation positions.

Brachioradialis originates from the lateral supracondylar ridge of the humerus. This anatomical placement allows efficient elbow flexion during functional tasks.

The radial nerve innervates the brachioradialis muscle. Despite being a flexor, its posterior compartment location explains its radial nerve supply.

The primary action of brachioradialis is elbow flexion, especially when the forearm is in a neutral position. It assists other flexors during lifting tasks.

The posterior fibers of the medial collateral ligament become taut in extreme elbow flexion. This provides stability against valgus stress during deep flexion activities.

The annular ligament encircles the radial head, stabilizing it during rotation. This allows smooth pronation and supination without joint dislocation.

The proximal radio-ulnar joint is a pivot joint, allowing rotational movement around a single axis. This design supports forearm rotation without compromising elbow stability.

The antebrachial fascia divides the forearm into anterior and posterior compartments. This separation supports muscle organization and functional efficiency.

Flexion and extension occur at the humero-ulnar joint due to its hinge-like structure. This movement is critical for positioning the hand in daily activities.