Sonographic evaluation of median nerve cross‐sectional area in a normal Iranian population: A cross‐sectional study

INTRODUCTION: Considering disagreements on the normal range of median nerve cross‐sectional area (MNCSA) and insufficient data in the Iranian population, this study aimed to measure normal MNCSA. METHODS: In this cross‐sectional study, bilateral upper limbs of 99 subjects were assessed by sonography, and MNCSA was measured at three levels: forearm, carpal tunnel inlet (CTI), and carpal tunnel outlet (CTO). The association between MNCSA and demographic factors was assessed. RESULTS: Mean MNCSA was 6.33 mm(2) at the forearm, 9.41 mm(2) at CTI, and 10.67 mm(2) at CTO. MNCSA was significantly higher in males (6.78 vs. 5.94 mm(2) at the forearm, 9.98 vs. 8.92 mm(2) at CTI, and 11.24 vs. 10.84 mm(2) at CTO in males and females, respectively) and taller (>170 cm) subjects in all three levels (6.69 vs. 6.03 mm(2) at the forearm, 9.80 vs. 9.02 mm(2) at CTI, and 11.27 vs. 10.12 mm(2) at CTO in taller and shorter subjects, respectively). MNCSA was not significantly associated with wrist ratio (WR) or body mass index (BMI). CONCLUSION: The normal MNCSA range in the Iranian population is 6.31 mm(2) (forearm) to 10.74 mm(2) (CTO). MNCSA is significantly higher in males and taller subjects but is not associated with BMI and WR.