The elbow joint is formed between the humerus and ulna. Which statement best describes this joint?

• A. The elbow joint is formed between the humerus and ulna and is a hinge joint that allows flexion and extension movements
• B. The elbow joint allows circumduction
• C. The elbow joint is a ball-and-socket joint
• D. The elbow joint is a pivot joint

Answer: (A)

At the elbow, the articulation between the humerus and ulna mainly forms a hinge joint, which allows bending and straightening of the forearm in the sagittal plane. This hinges on the articulation between the trochlea of the humerus and the trochlear notch of the ulna, providing simple flexion and extension movements. While the forearm can rotate, that rotation (pronation and supination) occurs primarily at the nearby proximal radioulnar joint between the radius and ulna, not at the elbow joint itself. The other ideas describe joints with different movement patterns: circumduction is typical of ball-and-socket or certain condyloid joints, a ball-and-socket joint is like the shoulder, and a pivot joint is the rotary joint between the radius and ulna at the forearm level.