Triquetral bone bone fragment on lateral views. The etymology derives from the Latin "triquetrus" which means "three-cornered." Therefore, it is sometimes also called the triangular bone or os triangulare. However, "os triangulare" may also refer to a nearby accessory bone. Triquetral bone The triquetral bone (; also called triquetrum, pyramidal, three-faced, and formerly cuneiform bone) is located in the wrist on the medial side of the proximal row of the carpus between the lunate and pisiform bones. It is on the ulnar side of the hand, but does not articulate with the ulna. It connects with the pisiform, hamate, and lunate bones.
Triquetral bone it is one of the carpal bones that form the carpal arch, within which lies the carpal tunnel. The triquetral bone may be distinguished by its pyramidal shape, and by an oval isolated facet for articulation with the pisiform bone. It is situated at the upper and ulnar side of the carpus. To facilitate its palpation in an exam, the hand must be radially deviated so that the triquetrium moves out from under the ulnar styloid process. The triquetrum may be difficult to find, since it also lies under the pisiform. The triquetral bone ossifies between 9 months and 50