Ultrasonography of median nerve mobility in the diagnosis of carpal tunnel syndrome

Abstract

Abstract Background Few studies on median nerve mobility in carpal tunnel were reported. The purpose of this study was to observe median nerve mobility in the carpal tunnel dynamically with ultrasound during wrist and fingers flexion and extension and define the abnormality between normal people and patients with carpal tunnel syndrome. Materials and Methods Thirty-two persons without symptoms of carpal tunnel syndrome and 18 patients with symptoms of carpal tunnel syndrome (10 patients confirmed by nerve conduction velocity/electromyography) were evaluated by high-resolution ultrasound (the SonoSite Titan high-resolution ultrasound; transducer: 5–10 MHz, 38-mm broadband linear array) with wrist and fingers in flexion and extension positions. The motions of median nerve and flexor tendons were observed. Result In our observation, median nerve will move from the volar side of the flexor tendons to the dorsal side of the flexor tendons smoothly through the tract between flexor pollicis longus and flexor digitorum superficialis of index when wrist and fingers flexed. In patients with carpal tunnel syndrome, the normal mobility of median nerve was absent. In 18 patients with carpal tunnel syndrome symptoms, there were 17 patients (94%) with positive findings in ultrasound examination. In 32 persons without the symptom of carpal tunnel syndrome, there were four cases with positive findings. Conclusions Median nerve has mobility in the carpal tunnel. In patients with carpal tunnel syndrome, the mobility was absent. Ultrasonography of median nerve mobility is helpful in diagnosing carpal tunnel syndrome. Its reliability and sensitivity should be further evaluated.