Tunnel of Guyon:

From: www.wheelessonline.com

- Discussion:
     - depression between pisiform & hook of hamate is converted into fibrosseous tunnel, the tunnel of Guyon, by pisohamate ligament;
     - roof is formed by volar carpal ligament and pisohamate ligament;
            - the ulnar nerve bifurcates within the canal into superficial and deep branches;
     - tunnel of Guyon is clinically significant because it contains ulnar nerve and artery & is site for compression injury;
            - consider anomalous muscles, ganglia, hamate fractures ect.

- Technique of Decompression:
     - the pisiform and the hamate are marked;
     - a curvilinear incision is made between the pisiform and the hamate, and is extended proximally across the
             wrist crease and is then continued along the medial border of the FCU;
     - the ulnar nerve and artery are identified beneath the FCU;
     - the deep dissection proceeds distally over the ulnar tunnel;
     - incise thru the palmaris brevis and palmar carpal ligament;
     - examine the floor of Guyon's canal, and attempt to identify any anomalous muscles or ganglion cysts;