Hypothenar hammer syndrome. A case report.

Hypothenar hammer syndrome is an uncommon injury of the ulnar artery in its passage through Guyon's canal, and has been associated with repetitive trauma. Its diagnosis requires of a high level of suspicion and a careful clinical interview. The appropriate treatment is not well defined in the literature, ranging widely from medical treatment to reconstructive surgery. A clinical case is presented of a 52 year-old healthy male, who presented with numbness of his fourth and fifth fingers after a trauma at the hypothenar eminence. The Allen test highlighted an absence of vascularisation from the ulnar artery, thus suspecting an ulnar artery thrombosis, which was later confirmed by angio-MRI. The thrombosed segment was resected and a by-pass with a forearm vein was performed to reconstruct the distal arterial flow, presenting with a good functional outcome at 6months follow-up.