The relationship of the superficial radial nerve and its branch to the thumb to the first extensor compartment.

Abstract

The superficial radial nerve and its branches are vulnerable during surgery for de Quervain tenovaginitis. We studied the proximity of the nerve branches to the first extensor compartment. We dissected 20 forearms of 11 cadavers and measured the branching point of the superficial radial nerve relative to the radial styloid. We defined the midline of the first extensor compartment and measured distances of nerves adjacent to it. The superficial radial nerve gave the lateral dorsal digital branch to the thumb at 50 ± 13 mm (minimum, 26 mm; maximum, 72 mm) proximal to the radial styloid. Average distances of the lateral dorsal digital branch to the thumb to the midline of first extensor compartment from proximal to distal were 2, 2, and 2 mm, respectively. In 8 forearms, the lateral dorsal digital branch to the thumb passed directly over the first extensor compartment along its entire length. We found that as the superficial radial nerve diverged from the first extensor compartment, its lateral dorsal digital branch to the thumb coursed parallel and in close relation to it. Anatomic knowledge of the course of the superficial radial nerve and its branches is important during open release for avoiding nerve injury. The close relation of the superficial radial nerve and its lateral dorsal digital branch to the thumb with the first extensor compartment may guide surgeons during surgery for de Quervain tenovaginitis.