Additional Muscle Belly and Abberant Muscle Fibers over the Extensor Retinaculam of Wrist

Variations in the extensor compartment of forearm are common and are significant to neurologists, surgeons and anatomists. The present case report describes a well-developed muscle belly medial to the tendons of extensor carpi radialis longus and extensor carpi radialis brevis. Muscle belly is originating from common extensor origin on lateral epicondyle and is inserted to base of third metacarpal; bilaterally. In addition to this, aberrant muscle fibres packed in a common connective tissue bundle over the dorsal digital expansion of left hand were also found. The above observations were noted during routine dissection of a 50 year old Indian male cadaver. The variant muscle having common extensor origin and muscle fibres over dorsal digital expansion were identified and protected. The blood supply and nerve supply were noted. The clinical significance of the variation is explained in detail.