Comstock observed chronic tenosynovitis due to variant connection between flexor pollicis longus and flexor

The accessory heads of the deep flexors of the forearm (Gantzer’s muscles) have been described as two different small bellies which insert either into flexor pollicis longus (FPL) or flexor digitorum profundus (FDP) [1]. It is not surprising to find that there are many variations in the manner in which the FPL and the FDP are combined, because both have a common phylogenic derivation from the pronatoflexor group of Humphry [2]. Most of the studies about these two muscle connections describe about the accessory head of FPL, which was taking origin from the coronoid process of ulna or from the medial epicondyle of the humerus. In the present case we observed a rare muscle belly which was arising from the FPL itself. Since this type of variation was not reported hitherto, the case was studied in detail. The embryological basis of this unusual condition is discussed with relevant review of literature and clinical significances are emphasized.