[Bilateral hypothenar hammer syndrome].

Hypothenar hammer syndrome is caused by ulnar artery occlusion subsequent to repeated blunt trauma such as by using the hypothenar as a hammer during work. Allen's test permits the detection of this frequent and often overlooked cause of hand pain and ischaemia. The four bilateral hypothenar hammer syndromes described in this case report occurred after several years of occupational exposure to hard shocks/impacts to the hypothenar from workpieces, which were held with a firm grip.