Assessment of ultrasonographic sizes of median and ulnar nerves and association with anthropometric measurements

Objective: The aim of this clinical trial was to obtain the association of cross-sectional area (CSA)`s of median and ulnar nerve with the anthropometric measurements in healthy individuals. Methods: 200 healthy volunteers were measured bilaterally. Age, sex, body mass index, and dominant extremity were recorded. Also, shoulder width, forearm, and upper arm length and forearm circumference were recorded. CSA of the nerves were defined with the ultrasonographical (USG) examination. The median nerve CSA measured at the level of scaphoid bone and the mid-point of the forearm. The ulnar nerve CSA was measured at the level of the hook of hamate and the mid-point of the forearm. Results: The results of the 118 women and 82 men was recorded. The average median nerve CSA at the level of scaphoid bone was 8.7±1.8, and at the mid-point of the forearm was 8.7±1.8. The average ulnar nerve CSA at the level of the hook of hamate was 6.3±1.4, and at the mid-point of the forearm was 7.5±1.9. There was no statistical difference in CSA between dominant and non-dominant arms. Men did have larger nerves than women. Of all the anthropometric measurements recorded, CSA correlated most closely with forearm circumference with a correlation coefficient of .721. Other than this bifid and trifid median nerve consecutively was seen in 9% and 3% of the healthy individuals. The CSA of the bifid and trifid median nerve was relatively higher than that of the non-bifid median nerve. Conclusions: The ulnar nerve was easily visualized and measured along its entire course, and the CSA of the nerve was consistent at multiple sites. The reference values obtained in this study will facilitate the analysis of abnormal nerve conditions, and the information on side-to-side variation and sex-specific differences should be particularly helpful