Vascular anatomy of the pisiformis bone.

The authors examined 41 dried pisiform specimens; it was found that the vascular apertures were situated on the lateral aspect, in the proximal half of the ridge occupied by the ulnar artery, on the medial aspect and at the distal tip of the bone. An average number of 6.9 foramina were encountered, their mean diameter attained 40/100 mm. In 34 injected specimens the nutrient vessels of the pisiforme were traced from the ulnar artery and its carpal dorsal and deep volar branches; all the tiny bony twigs anastomosed with one another and contributed to an arterial circle running around the pisiforme. The carpal dorsal artery which provides at least 2 descending branches toward the proximal tip of the bone, can be called the main pedicle; when its superficial branches are ligated, the pedicle is long enough (3 cm) to make the replacement of the lunate by the pisiform attached to the flexor carpi ulnaris quite safe in Kienböck's disease, without any risk of osteonecrosis.