Abstract: ［Abstract］ Objective〖HTSS〗〓To diagnose carpal tunnel syndrome by high frequency and electromyography（EMG）, and to study the diagnosis from two aspects of morphology and function.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Thirty patients and 30 healthy volunteers were tested in ultrasound and EMG respectively. The echo changes, left and right diameter, anteroposterior diameter and crosssectional area were observed by high frequency ultrasound. At the same time, distal motor latency and amplitude, middle finger to wrist sensory nerve conduction velocity and electrophysiological index of abductor pollicis brevis muscle were performed by EMG. The correlation analysis between the two methods was made. While the receiver operating characteristic(ROC) curve was used to determine the diagnostic value.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓In the carpal tunnel syndrome group, the median nerve echo was decreased, the internal punctate echo disorder was disappeared, the nerve swelling, the median nerve left and right diameter, anteroposterior diameter and crosssectional area were greater than those in the control group(P＜005). The latency of the median nerve was significantly prolonged, the amplitude was decreased, and the sensory conduction velocity was slowed down and amplitude was decreased(P＜005). The crosssectional area measured by high frequency ultrasound was positively correlated with the distal latency of the median nerve, and negatively correlated with the median sensory conduction velocity(P＜001). The diagnostic value of the crosssectional area obtained by ROC curve was the highest, with the sensitivity of 86.7% and the specificity of 93.3%.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓High frequency ultrasound can clearly display the shape of median nerve in wrist and measure the value of clamp pressure. The diagnosis of median nerve injury at the carpal tunnel can be performed by high frequency ultrasound and EMG.

Key words: carpal tunnel syndrome, ultrasonography, electromyography