Triquetral bone months (4 years and 2 months). The "superior surface" presents a medial, rough, non-articular portion, and a lateral convex articular portion which articulates with the triangular articular disk of the wrist. The "inferior surface", directed lateralward, is concave, sinuously curved, and smooth for articulation with the hamate. The dorsal surface is rough for the attachment of ligaments. The "volar surface" presents, on its medial part, an oval facet, for articulation with the pisiform; its lateral part is rough for ligamentous attachment. The "lateral surface", the base of the pyramid, is marked by a flat, quadrilateral facet, for articulation with the
Hamate bone bone has six surfaces: The "hook of hamate" () is found at the proximal, ulnar side of the hamate bone. The hook is a curved, hook-like process that projects 1–2 mm distally and radially. The hook forms the ulnar border of the carpal tunnel, and the radial border for Guyon's canal. Numerous structures attach to it, including ligaments from the pisiform, the transverse carpal ligament, and the tendon of Flexor carpi ulnaris. Its medial surface to the flexor digiti minimi brevis and opponens digiti minimi; its lateral side is grooved for the passage of the flexor tendons into the palm