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
Carpal tunnel to the pisiform and hook of hamate. The narrowest section of the tunnel is located a centimetre beyond the mid-line of the distal row of carpal bones where the sectional area is limited to 1.6 cm. The tendons of the flexor digitorum superficialis and profundus pass through a common ulnar sheath, while the tendon of the flexor pollicis longus passes through a separate radial sheath. The mesotendon shared by these tendons is attached to the radial and palmar walls of the carpal tunnel. Superficial to the carpal tunnel and the flexor retinaculum, the ulnar artery and ulnar nerve pass through