Which combination of bones forms the elbow joint?

• A. Humerus and Radius
• B. Radius and Ulna
• C. Humerus and Scapula
• D. Humerus and Ulna

Answer: (D)

The elbow joint is mainly defined by the connection between the distal end of the humerus and the ulna. The curved region of the humerus (the trochlea) fits with the ulna’s trochlear notch, creating the hinge that allows bending and straightening of the arm. The radius also contributes to elbow movement, especially for rotation, by forming joints with the humerus (the capitulum) and with the ulna at the proximal radioulnar joint, but the primary articulation that defines the elbow itself is between the humerus and ulna. That’s why the combination of humerus and ulna best forms the elbow joint. The scapula is part of the shoulder girdle and not involved in forming the elbow joint, and while the radius participates in the elbow complex, it does not define the main elbow articulation on its own.