Wrist Case 11 Background
The pisiform is a sesamoid bone within the tendon of the flexor carpi ulnaris that articulates with the triquetrum. It lies near the deep ulnar nerve and artery and fractures of the pisiform can cause ulnar nerve injuries.
Pisiform fractures are rare; they account for only 1-3% of all carpal bone fractures. There is a 50% incidence of associated injury to the distal radius or another carpal bone.