High-resolution sonography of the superficial radial nerve with two case reports.

The purpose of this study was to find out whether high-resolution sonography can be used to examine the superficial radial nerve. The sonographic appearance of the superficial radial nerve was assessed in 20 control subjects and the cross-sectional area could be measured in all subjects. The mean cross-sectional area of the superficial radial nerve in the control subjects was 2 mm(2) (SD 0.5 mm(2), range 1-3 mm(2)). Moreover, two patients with a superficial radial neuropathy and abnormal high-resolution sonography are reported. One patient had an enlarged nerve after trauma, which was probably a neuroma. The other patient had a histologically proven Schwannoma of the superficial radial nerve. The superficial radial nerve, although small in size, can be visualized by high-resolution sonography using specific landmarks. High-resolution sonography can be useful to assess the underlying cause of superficial radial nerve pathology.