Triquetrum Bone

Triquetrum or the triquetral bone (Latin: os triquetrum) is a three-sided or pyramid-shaped carpal or wrist bone ^{[1, 2]}. Its name is derived from the Latin word ‘triquetrus’, or ‘having three corners’ ^[3] – referring to the fact that it has three prominent articular surfaces ^[4].

It is one of the four proximal carpal bones, the third from the thumb ^[4], after the scaphoid and lunate. It is situated between the pisiform and lunate bones ^[3].

Triquetrum Bone

The triquetrum is the third bone to develop, ossifying during the second or third year of life ^{[5, 6]} (meaning it will be visible in an x-ray in a 2-3-year-old child). The order may be different in girls ^[7].

Triquetral Bone X-ray

It articulates with three of the carpal bones and thus has three major articular surfaces – the smallest one being an oval facet on the palmar surface for the pisiform bone ^[8]. The distal concave surface is meant for the hamate and is the largest of the articular facets [8]. The third surface articulating with the lunate is continuous with but lateral to, the hamate facet ^[4].

Triquetrum Bone Articular Surface Anatomy

The rough dorsal surface of the bone serves for all the ligament attachments ^[9].

The triquetrum receives its primary blood supply from the ulnar artery ^[10]. It is supplied on its two non-articular surfaces by a network of nutrient vessels ^[3].

Its primary function is to shape up and maintain the flexibility of human wrists along with the other carpal bones.

The triquetrum is the third most commonly fractured carpal bone, often occurring due to overextension of the wrist, like during a fall or when playing sports ^[11].