Relationship between the ulnar artery and transverse carpal ligament

Anatomic relationship between the ulnar artery and transverse carpal ligament (TCL) was investigated to help planning for minimally invasive carpal tunnel surgery. The anatomic course of the ulnar artery and its branches toward the TCL were determined in twenty-four fresh cadaver hands. The ulnar artery coursed ranging 7 mm ulnar to 2 mm radial to the hamate hook. A small arterial branch branching directly from the ulnar artery ran transversely just over the TCL in six of the 24 specimens. The location of this branch was consistently within 15 mm proximal to the distal margin of the TCL. These and other microscopic observations indicated that the ligament release at 5 mm radial to the hamate hook is suitable to reduce postoperative bleeding and to prevent vascular and neural injury.