The lunate gets its name from its semilunar shape. The lunate is convex proximally and articulates with the concave radius and the articular disc. Its narrow lateral surface bears a flat semilunar facet for the scaphoid. The medial surface, which is almost square, articulates with the triquetrum. The distal surface is concave anteroposteriorly where it articulates with the capitate and a small portion of the hamate.