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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.

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Brachial plexus is the plexus of nerves that supplies the upper limb. The anterior divisions of upper and middle trunks form lateral cord and that of the lower trunk form medial cord. Posterior divisions of all the three trunks form the posterior cord. Here we report a case of unilateral variation in the formation of medial cord of brachial plexus during dissection of a female perinatal cadaver of 34 weeks of gestation which was dissected as a part of Congenital Malformation Survey conducted in the Department of Anatomy, Assam Medical College, Dibrugarh with necessary ethical clearance. Medial cord was formed by the anterior division of lower trunk and this cord had a communication from the posterior division of middle trunk. It is very important to be aware of the variations of the cords of the brachial plexus during different invasive procedures in that region.