Triquetral bone

Triquetral bone
Bone: Triquetral bone
Shown is the right hand, palm down (left) and palm up (right).
Proximal: A=Scaphoid, B=Lunate, C=Triquetral, D=Pisiform
Distal: E=Trapezium, F=Trapezoid, G=Capitate, H=Hamate
The left triquetal bone
Latin os triquetrum, os pyramidale, os triangulare
Gray's subject #54 224
Articulations articulates with three bones:
lunate laterally
pisiform in front
hamate distally
triangular articular disk which separates it from the lower end of the ulna.  
MeSH Triquetrum+Bone

The triquetral bone (also called triquetrum, pyramidal, three-cornered or triangular bone, 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. It is the 3rd most commonly fractured carpal bone.

The triangular 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 etymology derives from the Latin triquetrus which means "three-cornered." In reptiles and amphibians, the bone is instead referred to as the ulnare, since (at least in the most primitive fossils) it articulates with the ulna.


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 lunate.

The medial surface, the summit of the pyramid, is pointed and roughened, for the attachment of the ulnar collateral ligament of the wrist.

See also

Additional images

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Look at other dictionaries:

  • triquetral bone — noun One of the carpal bones of the wrist. Syn: triquetral, triquetrum, os triquetrum, cuneiform bone, pyramidal bone, cubital bone, os pyramidale, os triangulare, three cornered bone, triangular bone …   Wiktionary

  • triquetral bone — noun a wrist bone that articulates with the pisiform and hamate and lunate bones • Syn: ↑triquetral, ↑os triquetrum, ↑cuneiform bone, ↑pyramidal bone • Hypernyms: ↑carpal bone, ↑carpal, ↑wrist bone …   Useful english dictionary

  • triquetral bone — tri·que·tral bone trī kwē trel n the bone in the proximal row of the carpus that is third counting from the thumb side of the wrist, has a pyramidal shape, and is situated between the lunate and pisiform bones called also triangular, triangular… …   Medical dictionary

  • triquetral bone — triquetrum …   The new mediacal dictionary

  • triquetral — noun a wrist bone that articulates with the pisiform and hamate and lunate bones • Syn: ↑triquetral bone, ↑os triquetrum, ↑cuneiform bone, ↑pyramidal bone • Hypernyms: ↑carpal bone, ↑carpal, ↑wrist bone …   Useful english dictionary

  • triquetral — (also triquetral bone) noun Anatomy a carpal bone on the outside of the wrist, articulating with the lunate, hamate, and pisiform bones. Origin C17: from L. triquetrus three cornered + al …   English new terms dictionary

  • triquetral — 1. adjective Three cornered Syn: triquetrous 2. noun The triquetral bone …   Wiktionary

  • Bone — is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate. It also serves as a storage area for calcium, playing a large role in calcium balance in the blood. The 206 bones in the body …   Medical dictionary

  • Кость Трехгранная (Triquetrum, Triquetral Bone) — кость запястья (см. Запястье). Сверху она соединяется с локтевой костью, а также с гороховидной, крючковидной и полулунной костями запястья. Источник: Медицинский словарь …   Медицинские термины

  • Bone — This article is about the skeletal organ. For other uses, see Bone (disambiguation) and Bones (disambiguation). For the tissue, see Osseous tissue. Drawing of a human femur Bones are rigid organs that constitute part of the endoskeleton of… …   Wikipedia

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