Incidence of Accessory Head Of Flexor Pollicis Longus (Only In Males) and Its Clinical Significance.

Background & objectives: Accessory muscle slips may arise from coronoid process of ulna or medial epicondyle of humerus and it joins to flexor pollicis longus muscle. This accessory muscle slip is known as accessory head of flexor pollicis longus or Gantzer's muscle. It runs downward and obliquely to join the flexor pollicis longus. While coursing it may compress median, ulnar and anterior interosseous nerves and produce neurological conditions. Aim of our study was to observe incidence of accessory head of flexor pollicis longus in adult. Method: We studied 60 upper limbs (rt: 30; lt: 30) of adult male Indian cadavers. Each forearm was dissected carefully to see the presence of accessory heads of the flexor pollicis longus and its relations with nearby structures. Results: Accessory head of flexor pollicis longus was observed in 35 upper limbs out of 60 (58.33%). It was present in 31.66 % (19) in right side and 26.66% (16) in left side upper limbs. We observed that, the median nerve ran over the accessory head of flexor pollicis longus while the anterior interosseous nerve ran posteriorly. Conclusions: Incidence of accessory head of flexor pollicis longus was high and its relation to the median nerve, anterior interosseous nerve and ulnar artery is important. Therefore, precise knowledge about this muscle is essential which will help the clinician, surgeon and radiologist to determine the exact cause of entrapment. [ABSTRACT FROM AUTHOR]