Dimensional changes of the carpal tunnel and median nerve during manual mobilization of the carpal bones — Anatomical study.

Abstract Study design Cross-sectional study. Background The carpal tunnel is a clinically important fibro-osseous conduit for the median nerve and associated tendons. It is mechanically dynamic and therapeutic manual techniques that appear to move and change tunnel shape is part of clinical practice. Objectives To measure changes in dimensions of the carpal tunnel and median nerve with manual mobilization of the carpal bones in cadavers. Methods A total of 20 cryopreserved upper extremities from cadaveric specimens were used in the study. The wrist was cut using an anatomical saw at the level of the pisiform. Measurements of the cross-sectional area (CSA), anteroposterior diameter (APD), transverse diameter (TD), perimeter, flattening ratio and circularity of the carpal tunnel and of the median nerve, were taken, both in the anatomical position of the wrist and during the mobilization technique of the carpal bones. Results During the mobilization technique, the tunnel CSA (p < 0.011), APD (p < 0.001) and circularity (p < 0.001) significantly increased, while TD (p < 0.001), perimeter (p < 0.004) and flattening ratio (p < 0.001), decreased. The median nerve showed similar behavioral tendencies to the tunnel but only the CSA (p < 0.005), APD (p < 0.005) and flattening ratio (p < 0.004) of the nerve showed significant differences. Conclusion Application of external manually applied compressive force across the wrist can increase the CSA of the carpal tunnel and the median nerve in cadavers. These results are consistent with other studies in which similar results were found non-invasively using ultrasound. Highlights • Cross-sectional area of the carpal tunnel increased during the manual mobilization of the carpal bones in cadaver. • The mobilization increased the anterior-posterior diameter of the carpal tunnel. • Both the carpal tunnel and the median nerve became rounder during the technique. [ABSTRACT FROM AUTHOR]