Common variations in muscles and tendons of the hand were determined by dissecting 40 pairs of hands (20 male, 20 female). Contrary to some anatomy textbooks which describe only three palmar interossei, with the thumb lacking one, this study found four palmarinterossei present in 85% of hands and 90% of bodies. This first palmar interosseous typically arose from the base of the first metacarpal and inserted along with the tendon of the oblique head of adductor pollicis into the base of the proximal phalanx. Forty hands (50%) did not have the usual arrangement of lumbricals. Twenty-seven (34%) third lumbricals and four (5%) fourth lumbricals split at their insertions; four third lumbricals and four fourth lumbricals inserted on the ulnar side of the middle and ring fingers, respectively. T h e abductorpollicis longus inserted by 2 or 3 tendons in 91% of hands. T h e tendon of extensordigiti minimi split into 2 or 3 slips in practically all of the hands studied (96%). T h e tendon ofextensorindzcis split into 2 slips in more than a third (38%) of hands. In almost a third (30%) of hands there were accessory extensor muscles present deep to the tendons of extensor digitorum. Lastly, extra slips of origin of the abductordigitiminimi were present in 10% of hands. This study confirms the presence of a palmar interosseous muscle for the thumb and demonstrates that some variations occur more frequently than was expected.