"Dangerous" anatomic varieties of recurrent motor branch of median nerve.

UNLABELLED Carpal tunnel release became one of the most common operations in the field of hand surgery. Many controversies has been made about frequency of the so-called dangerous variations of motor branch of the median nerve. Knowledge of all the anatomical variations motor branches is the duty of every surgeon dealing with the subject. The aim of the study was to present the incidence of dangerous variants of median nerve motor branch in the carpal tunnel based on both clinical experience and anatomical studies performed on 20 cadaver wrists. MATERIAL AND METHODS Between 2006-2012 during minimally open carpal tunnel release we made photographic documentation of all visible dangerous varieties of recurrent motor branches of the median nerve. We also studied 20 cadaver wrists in the Department of Anatomy Medical University in Wrocław. RESULTS Dangerous varieties of the motor branch of median nerve was found in three clinical cases and in one cadaver wrist. Also In one wrist we found one regular branche, which, however, has atypical two separate branches supplying the thenar muscles. CONCLUSIONS Dangerous varieties of the motor branch of median nerve occur very rare in the population, but does not release from the fact that in each case special attention must be given.We also conclude that, at the minimally open carpal tunnel release procedure, the transverse carpal ligament should be released rather from the line of radial border of the 4th finger to minimize the risk of injury to the recurrent motor branch of median nerve.