The present work seeks to compare the diameter of the wombs of the muscle brachial biceps and m. brachial in the intention of settling the doubts on which would be the most potent muscle in the flexing of the forearm. The measures were accomplished in 50 superior members of fastened corpses. A medium difference of 0.51 cm (5.8%) was evident in the diameter of the muscular womb the largest for m. brachial, ratifying what was found in the bibliographical revision, that brachial muscle is an important flexor of the elbow.