A Man with Numbness in the Hands

摘要

A 38-year-old man had a 4-month history of numbness in both hands. The numbness was triggered by riding a motorcycle. Examination showed no wasting of both thenar eminences. A Phalen's maneuver elicited tingling in the right middle finger after 30 s. Tinel's sign could not be induced on percussion of the median nerves at the wrist. Neither weakness nor sensory loss was found. Electrodiagnostic examination was performed and there is neurophysiologic evidence of moderate median nerve dysfunction at both wrists. Ultrasound imaging was done at both wrists for guiding steroid injection. Figure 1 shows left and right median nerves at the wrists. What is your diagnosis?