The structure indicated is the triquetral bone
of the hand.
There are three groups of bones
in the hand:
- Carpal bones (8 in total)
- Metacarpal bones
The carpal bones are separated into two rows
- Proximal row
- Distal row
The triquetral bone is one of four bones
in the proximal row of carpals (scaphoid, lunate, triquetral, pisiform). The triquetral bone is located medially
in the hand and articulates with the pisiform
bone, the hamate
bones. On the medial aspect of the volar surface of the triquetral bone is a facet
for articulation with the small pisiform bone.
Learn more about the anatomy of the bones
of the hand in this tutorial.