Tendon variations related to extensor muscles of the hand in both upper extremities were detected during the routine dissection of a 70-year-old male cadaver. Even if one nerve supplying the muscles with the same function and different nerve supplies is injured, the function can be preserved partly because the movement is tolerated by other muscles. If there is a common tendon among these muscles, the movement is not lost. Due to the tendon between extensor carpi radialis longus and brevis muscles, these muscles move together and their function is strengthened. The tendons of extensor muscles help stabilize the hand during forced graping and provide the loosness needed for sensitive finger movements independent from each other. Knowledge of normal anatomy and variations in the tendons of extensor muscles is important for identification of accessory tendons and repair of the functions.
Keywords: Extensor carpi radialis brevis muscle, extensor carpi radialis longus muscle, variation
