The raised smooth surface on the lateral aspect of the distal humerus is known as what?

• A. Capitulum
• B. Trochlea
• C. Coronoid fossa
• D. Radial head

Answer: (A)

The raised smooth surface located on the lateral aspect of the distal humerus is known as the capitulum. This anatomical structure plays a vital role in the elbow joint, providing a smooth surface for articulation with the radial head during forearm movements. The capitulum is specifically designed to facilitate movement and reduce friction where the radius meets the humerus, thereby aiding in the range of motion for the elbow.

In contrast, the trochlea is situated medially and primarily articulates with the ulna, forming another critical component of the elbow joint. The coronoid fossa is a depression above the trochlea that helps accommodate the coronoid process of the ulna during flexion and extension of the elbow. The radial head, while an important structure in the forearm, serves a different role as the proximal end of the radius that interacts with the capitulum.

Understanding the capitulum’s location and function is crucial for interpreting elbow anatomy, particularly when assessing joint stability and potential injuries related to the distal humerus.