Evaluation of bifid median nerve with sonography and MR imaging

Bifid median nerve is an anatomic variation that may be associated with car pal tunnel syndrome. It is important for the surgeon to be aware of the exi stence of this condition preoperatively in order to plan the carpal tunnel release. We report the correlation between ultrasonographic findings and ma gnetic resonance imaging results in six patients with bifid median nerve, s elected from a population of 294 patients with carpal tunnel syndrome, who were studied by ultrasonography using a high frequency transducer. Sonograp hy showed two structures inside the carpal tunnel with the same pattern as the median nerve in all six patients. Magnetic resonance imaging confirmed the sonographic findings. The patients underwent open surgery, and a bifid median nerve was found. In conclusion, bifid median nerve is an anatomic va riant that can be demonstrated ultrasonographically. It is important to be aware of this anomaly when planning carpal tunnel release surgery.