PMC5943862_01
Typical case of radial nerve compression. Images were obtained from a 32-year-old woman who was admitted because of extensible wrist and numbness. A, Electrophysiological examination results of the motor branch of the radial nerve. B, Electrophysiological examination results of the sensory branch of the radial nerve. C, EMG result when the muscle was relaxed. D, EMG result when the muscle was contracted with small force. E, EMG result when the muscle was contracted with large force. F, Ultrasonography results. LRN = left radial nerve. RRN = right radial nerve. G, Deep radial nerve release surgery was performed. The arrows indicate the swelled and thickened radial nerve after compression.
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F1
AMP of the motor branch of the radial nerve decreased to 0.6 mv and the motor NCV of the elbow-radial nerve decreased to 39.4 m/s (Fig. 1A). As shown in Figure 1B, the AMP of the sensory branch of the radial nerve decreased to 5.9 uv and the sensory NCV was 55.6 m/s (Fig. 1B). On EMG, the denervation potential was observed when the muscle was relaxed (Fig. 1C). The duration of MUP increased to 13.3 ms and the AMP of MUP decreased to 235.7 uv when the muscle contracted with small force (Fig. 1D). When the muscle contracted with large force, the recruitment AMP was 1.2 mv (Fig. 1E). Ultrasonography showed that the deep branch of the left radial nerve increased to 0.3 cm and the echo reduced (Fig. 1F, left). The right radial nerve deep branch was normal (Fig. 1F, right). Surgery showed that the compression was caused by the arcade of Frohse (Fig. 1G).
Typical case of radial nerve torsion. Images were obtained from a 35-year-old male who was admitted because of wrist drop for a week. A, Electrophysiological examination results of the motor branch of the radial nerve. B, Electrophysiological examination results of the sensory branch of the radial nerve. C, EMG result when the muscle was relaxed. D, EMG result when the muscle was contracted with small force. E, EMG result when the muscle was contracted with large force. F, Ultrasonography results. DN = deep nerve, SN = superficial nerve. G, Torsion nerve resection and sural nerve transplantation were performed. During surgery, it was observed that the thickened deep branch of radial nerve had two torsions.
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F2
Electrophysiological examination showed that the AMP of radial nerve groove decreased to 0.1 mv, and the NCV of elbow- radial nerve groove decreased to 32.7 m/s (Fig. 2A). The AMP of the sensory branch of the radial nerve decreased to 3.2 uv and the sensory NCV was 42.7 m/s (Fig. 2B). On EMG, there was denervation potential when the muscle was relaxed (Fig. 2C). When the muscle contracted with small force, the duration of MUP increased to 12.5 ms and the AMP of MUP decreased to 420.2 uv (Fig. 2D). The recruitment AMP was 1.6 mv when the muscle contracted with large force (Fig. 2E). The ultrasonography showed that the deep branch of the left radial nerve was significantly thicker (Fig. 2F, left). The vertical axis of ultrasonography showed that the left deep branch of radial nerve showed hourglass-like changes, presenting as thinned torsion, reduced echo at the thickened nerve ends without compression and unclear internal structure (Fig. 2F, right). During surgery, we observed that the thickened deep branch of radial nerve had two torsions (Fig. 2G).