The normal reference values may be helpful in diagnosis of pathologies involving these nerves.

The lower extremity nerve CSA values obtained in this study may provide normal reference values for the Asian population.

Introduction Neuromuscular ultrasound is a painless, radiation-free, and high-resolution imaging modality for assessment of the peripheral nervous system. The purpose of this study was to use neuromuscular ultrasound to assess the changes that occur in the median nerve following steroid injection for carpal tunnel syndrome (CTS). Methods Ultrasound and nerve conduction studies were performed at baseline and 1 week, 1 month, and 6 months after steroid injection in 19 individuals (29 wrists) with CTS. Results Significant changes were noted in median nerve cross-sectional area (p<0.001), mobility (p=0.001), and vascularity (p=0.042) at the distal wrist crease following steroid injection, and the nerve cross-sectional area correlated with symptom score and electrodiagnostic parameters. Changes in the ultrasonographic parameters were seen within one week of injection. Discussion These findings suggest neuromuscular ultrasound is potentially helpful for the assessment of individuals undergoing treatment for CTS, as typical changes can be expected following successful treatment.