Hook of the hamate

Study entry

Description

Hook-shaped process that projects into the palm from the hamate.

Relations

Origin of the flexor digiti minimi brevis and of the opponens digiti minimi; insertion of the flexor carpi ulnaris; lateral limit of the ulnar canal.

Clinical

Prolonged pressure on the hooks (cyclists) compresses the ulnar nerve.

Source: cap. 3, «Huesos de la mano»

Clinical correlation

Fracture of the hamate

The muscles attached to the hamate pull the fragments and may prevent union. The ulnar nerve passes next to the hook and may be injured, weakening the grip; the ulnar artery may also be affected.

Ulnar canal syndrome (Guyon's canal) and handlebar neuropathy

At the wrist, the ulnar nerve may be compressed between the pisiform and the hook of the hamate, in an osteofibrous canal closed by the pisohamate ligament (Guyon's canal). It causes loss of sensation in the little finger and part of the ring finger and weakness of the intrinsic muscles of the hand. There may be clawing of the 4th and 5th fingers, but, unlike a high ulnar lesion, finger flexion continues and the hand does not deviate to the radial side.

Related clinical cases

• Fracture of the hamate
• Ulnar canal syndrome (Guyon's canal) and handlebar neuropathy

Other structures in this region

• Conoid tubercle
• Trapezoid line
• Scapular notch
• Glenoid cavity
• Supraglenoid tubercle
• Infraglenoid tubercle
• Subscapular fossa
• Supraspinous fossa