Ultrasound reference values for peripheral nerve cross-sectional areas and indices in a sample of healthy individuals in Brazil.

Among individuals in Brazil, peripheral nerve CSA values tend to be higher among males and to increase with aging. However, the same does not appear to hold true for the ΔCSA or the ΔTPT, the exception being the difference between the right and left UT. Differences in CSA values greater than 2.5 mm between sides or between sites along the same nerve can indicate asymmetry or focal thickening in neuropathy, respectively.