The purpose of this study was the presence of accessory tendon and its anatomical variation of insertion of the abductor pollicis longus and extensor pollicis brevis. 1. Among 46 cases, all had one or more accessory tendon except one which inserted into the base of the first metacarpal bone on its anterolateral surface with a single tendon. 2. Among 45 cases (which had one or more accessory tendon), the abductor pollicis longus tendon inserted into the trapezium in 30 cases(66.6%), and thenar muscles in 38 cases (84.4%). 3. Among 46 cases, the extensor pollicis brevis tendon inserted into the proximal phalanx in 30 cases(65%) and into the distal phalanx with extensor pollicis longus in 8 cases (18%) and into both in 8 cases (18%). 4. Among 22 cadavers, symmetry of insertion of the abductor pollicis longus noticed in 16 cases (88 and extensor pollicis brevis in 21 cases (95%).