This study investigated which anatomic landmarks were most useful for correct and safe incision placement
in carpal tunnel surgery. Kirschner wires were attached to the hands to mark previously defined landmarks.
The bony attachments of the transverse carpal ligament, which were identified previously, were drawn on an
anteroposterior digital x-ray of the hand, with the thumb in full abduction. The relationship between anatomic
landmarks and these bony attachments were examined. In all hands, either the line along the third web space
or the crease between the thenar and the hypothenar regions, or both, were on the ulnar half of the transverse
During incision placement, we recommend selecting the most ulnar choice between the line
drawn along the third web space and the crease between the thenar and hypothenar regions in order to be at
safe distance from the recurrent motor branch of the median nerve.