Effect of Force, Posture, and Repetitive Wrist Motion on Intraneural Blood Flow in the Median Nerve

Objectives Pinching, deviated wrist postures, and repetitive motion are risk factors for carpal tunnel syndrome. Hypervascularization of the median nerve and increased intraneural blood flow proximal to the carpal tunnel result in finger force and deviated wrist postures. The purpose of this study was to determine the effects of pinching with and without force, wrist posture, and repetitive wrist motion on intraneural blood flow in the median nerve. Methods Eleven healthy and 11 carpal tunnel syndrome–symptomatic individuals completed 3 sections of this study: 15 pinch posture force trials, 3 repetitive wrist motion trials, and 3 static wrist posture trials. Intraneural blood flow (centimeters per second) was measured with pulsed wave Doppler ultrasound during each trial. Transverse B‐mode images obtained from static trials were used to calculate the median nerve cross‐sectional area and circumference. Results An analysis of variance statistical analysis revealed significant main effects of pinch posture force (F4,80 = 21.397; P