Coexistence of trifid and bifid median nerve in a patient with bilateral carpal tunnel syndrome.

Carpal tunnel syndrome is the most common upper extremity neuropathy in the wrist that may be associated with anatomic variations of median nerve. Trifurcation of the median nerve has been very rarely reported in the literature. We report coexistence of bilateral median nerve variation in the wrist and its radiological features. Ultrasonography and magnetic resonance imaging was performed to the patient after Tinel and Phalen tests. There was bifurcation and trifurcation of the median nerve in right and left wrists respectively. Bilateral carpal tunnel syndrome was caused by bilateral median nerve variation in the present case. When a median nerve variation is detected in one wrist, a possible variation at the other side should be kept in mind and hence should be evaluated. A thorough knowledge of the variations of the median nerve is essential in order to avoid surgical complications and to ensure optimal patient outcome. US is an easy and cheap radiological method for diagnosis and it should be the first chosen radiological technique to evaluate median nerve variations in idiopathic CTS patients.