Ulnar Tunnel Syndrome (Guyon’s Canal Syndrome)
The tunnel of Guyon is located on the palmar and medial (little finger) side of the wrist and is a tunnel composed of the pisiform and hook of the hamate (wrist bones) and surrounded by ligaments and muscles. It is through this tunnel that the ulnar artery and ulnar nerve travel. Entrapment or irritation of the ulnar nerve as it passes through this tunnel is called Guyon’s Canal Syndrome and can result in numbness, tingling and/or pain travelling into the 4th and 5th digits. Activities that cause compression over this location include cycling or operating vibrating machinery, other reasons include ganglions or fractures of the wrist bones.