A Unique Variation of Flexor Digitorum Superficialis Muscle and Its Clinical Significance

Abstract

KEYWORDS Additional Flexor Muscles. Flexor Digitorum Superficialis Indicis. Gantzer 's Muscle. Carpal Tunnel Syndrome ABSTRACT A wide array of supernumerary and accessory musculature of forearm has been described in the anatomical, surgical and radiological literature. In majority of the cases, these accessory muscles are asymptomatic but in some cases, these accessory muscles produce clinical symptoms. They may be present as a palpable soft swelling or as a fibro-osseous mass near carpal tunnel with symptoms of neurovascular compression. In symptomatic cases, recognition and careful evaluation of accessory muscle with electromyographic examination may aid in diagnosis and in finalizing the treatment. We report a rare case of accessory muscle bellies arising from Flexor Digitorum Superficialis (FDS) muscle on right and left sides. During routine dissections of the forearm performed by preclinical students in the department of anatomy , we observed an accessory muscle belly arising from the tendon of index finger of flexor digitorum superficialis muscle on the right and left sides of a cadaver . The accessory muscle belly has taken its origin at the junction of upper two third and lower one third of forearm and traversed in the carpal tunnel and merged with the tendon of FDS to the index finger in the hand at the level of origin of first lumbrical. Although many anatomical variations of FDS muscle were reported in the past, we describe a rare case, first of its kind, which to our knowledge has not been mentioned in the literature till date.