English

Abstract

BACKGROUND: Accessory head of Flexor pollicis longus in the forearm is one of the factors for causing anterior interosseous nerve syndrome. The objectives were to study the incidence, morphology of accessory head of flexor pollicis longus and its relation with median nerve and anterior interosseous nerve. METHODS: The present study was observational and descriptive type. A total of 60 upper limbs from 30 cadavers were dissected in the Department of Anatomy. The accessory head of flexor pollicis longus muscle was identified and its relation with median and anterior interosseous nerve was observed. The shape, origin and insertion of accessory head of flexor pollicis longus were noted. The length and width of the muscle belly and tendon were measured with digital vernier caliper. The findings were compared with that of previous studies. RESULTS: The accessory head of flexor pollicis longus was present in 13(43.3%) cadavers. The shape of muscle was fusiform in 84.61% and slender in 19.38%.Commonest site of origin was coronoid process of ulna (53.33%)., from the medial epicondyle 33.33% and 6.66% each form tendon of brachialis and deep head of pronator teres respectively. The average length and width of muscle belly were 93.48 ± 1.76mm and 7.03 ± 1.43 respectively. The tendon length and width were 20 ± 8.09mm and 0.55 ± 0.23mm. The median nerve was running anteriorly and the anterior interosseous nerve laterally to the muscle belly in all the cases. CONCLUSION: The presence of accessory head of flexor pollicis longus can be an important factor in anterior interosseous nerve syndrome, pronator teres syndrome. The results obtained in the present study would be useful for both physicians and surgeons to know the cause and therefore an appropriate management of the clinical syndromes.