RESTRICTED MOTION OF THE MEDIAN NERVE IN CARPAL-TUNNEL SYNDROME

Motion of the median nerve was compared on an axial ultrasonographic i mage in the mid-carpal tunnel in 30 wrists of 15 women with bilateral idiopathic carpal tunnel syndrome and 30 wrists of 15 healthy women. D uring passive flexion and extension of the index finger, the control w rists had transverse sliding of the nerve beneath the flexor retinacul um (1.75+/-0.49 mm), which was regarded as a physiological phenomenon. In contrast, the wrists of patients with carpal tunnel syndrome had s ignificantly less sliding (0.37+/-0.34 mm; P=0.0001), which indicates that physiological motion of the nerve is restricted. This decrease in nerve mobility may be of significance in the pathophysiology of carpa l tunnel syndrome.