A study on variations of branching patterns of median nerve in the carpal tunnel

Abstract

Background & aims: The carpal tunnel, located on the palmar surface of the wrist, is a common site of median nerve compression. The median nerve, on passing through the carpal tunnel, divides into lateral and medial branches. The lateral branch then gives off proper palmar digital branches to the thumb and the radial aspect of the index finger, and a recurrent muscular branch to the thenar muscles. The recurrent muscular branch shows different types of variations of the median nerve. Also, there are other variations of the median nerve in the carpal tunnel. These variations greatly influence the symptoms, as well as the treatment of the carpal tunnel syndrome. So, the present work is carried out to study the variations of branching patterns of median nerve in the carpal tunnel. Materials and methods: 40 wrists [20 right and 20 left] from 20 formaldehyde fixed human perinatal fetuses of 34 - 38 weeks of gestation were dissected in the Department of Anatomy, Gauhati Medical College and Hospital, Guwahati. Due ethical clearance was obtained from the Institutional Ethical Committee, Gauhati Medical College and Hospital, Guwahati. Results: In the present study, 24 [66.7%] hands [11 right and 13 left] showed extraligamentous and 12 [33.3%] hands [8 right and 4 left] showed transligamentous variety of thenar branch of median nerve. Also, 4 [10%] hands showed accessory thenar branch of median nerve, all of which took origin within the flexor retinaculum. The comparisons of numbers of variations of thenar branch of median nerve between right and left hands were found to be statistically non significant [P > 0.05]. Conclusion: A detailed knowledge of the median nerve variations in the carpal tunnel is required for successful diagnosis and treatment of the carpal tunnel syndrome and its complications.