The main anatomical feature of the hamate bone is the hamulus, a bony projection located at the distal portion of its palmar surface.
The main function of this bone is to connect the distal row of carpal bones with the fourth and fifth metacarpal bones. The hamate bone serves as the attachment point for a number of muscles and ligaments of the hand and forearm. In addition, it participates in the formation of the carpal tunnel and Guyon's canal.
This article will discuss the anatomy, structure and functions of the hamate bone.
|Definition||An irregularly-shaped bone located in the distal carpal row of the hand|
|Articulations||Proximally: Lunate bone
Distally: Fourth and fifth metacarpals
Medially: Triquetrum bone
Laterally: Capitate bone
Muscles: flexor digiti minimi brevis, opponens digiti minimi, abductor digiti minimi, flexor carpi ulnaris
Ligaments: flexor retinaculum, pisohamate ligament, triquetrohamate ligament, capitohamate ligament
|Functions||Muscle and ligamentous attachments
Connects fourth and fifth metacarpals to the carpus
Participates in the formation of the carpal tunnel and Guyon's canal
The hamate bone is a wedge-shaped bone located in the hand. It is the most medial of bones in the distal carpal row, being surrounded by three other carpal bones; the capitate, triquetrum and lunate bones. The body of the hamate bone has six surfaces: medial and lateral, proximal and distal and palmar and dorsal.
The palmar surface of the hamate contains a hook-like osseous projection called the hamulus (or hook) of the hamate bone. The hamulus is curved with a lateral concavity and its tip inclines laterally. The hamulus contributes to the formation of the medial wall of the carpal tunnel and the lateral wall of the ulnar canal (i.e. Guyon's canal). The hamulus also serves as the attachment point for a number of different muscles and ligaments of the hand and forearm, including the flexor retinaculum.
The hamate bone articulates with several adjacent bones:
- The proximal surface articulates with the lunate bone;
- The distal surface articulates with the fourth and fifth metacarpal bones;
- The medial surface articulates with the triquetrum;
- The lateral surface articulates with the capitate.
The hamate bone serves as the attachment point for several ligaments and muscles.
The ligamentous attachments include:
- The flexor retinaculum (also known as the transverse carpal ligament);
- The pisohamate ligament, connecting the pisiform bone and the hook of hamate;
- The triquetrohamate ligaments, between the triquetrum and the hamate;
- The capitohamate ligaments, between the capitate and the hamate.
The muscular attachments include:
- The flexor digiti minimi brevis muscle;
- The opponens digiti minimi muscle;
- The abductor digiti minimi muscle;
- The flexor carpi ulnaris muscle.
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