Introduction: Detailed information of structural and functional anatomy of thenar muscle is very significant in order to improve diagnostic and various conditions of hand surgeries so that the function of hand movement can be re-stored and to prevent further iatrogenic injuries. Methods: In this study, fifty hands were dissected to determine the variation in each of the thenar muscle. Results: Only the abductor pollicis brevis showed significant findings. Normal formation of one belly in abductor pollicis brevis represented 72.0% (18) and 84.0% (21) for the left and right hands, respectively. Variations according to the number of belly of the abductor pollicis brevis were also observed. One of the variations is the absence of the abductor pollicis brevis, 4.0% (1) in the right hand. Two belly formations of abductor pollicis brevis were observed, 28.0% (7) and 12.0% (3) for left and right sides of hand respectively. Thus, more variations were observed to occur on the left hand (7) compared to the right hand (4). Many studies describe about the variations of each thenar muscle, but few literatures were found discussing on the association of thenar muscle variation with the sides of hand. Using the Fisher Exact Test, it showed that there was no significant associa-tion of variations in the thenar muscle in relation to the sides of hand. Conclusion: This study conclude that there is no consistency between variations of the thenar muscle in relation to the sides of hand. However, clinical awareness of these variations is important in the context of compartment syndrome, use of the aberrant structures as grafting material in reconstructive surgery and proper interpretation of imaging modalities.