Electrophysiological and Histological Studies on the Human Skeletal Muscle Part Ⅱ The differentiation of Human Skeltal Muscle Fibers

Muscles of the rectus abdominis, the pectoralis major, the gastrocunemius and the tibialis anterior of the human being were stained with Sudan Black B in order to differentiate red and pale muscle fibers. 1. In the rectus abdominis, the ratio of red muscle fibers and pale muscle fibers is almost constant, and there is no relation between Rohrer's index and the ratio. Diameters of fibers vary with each muscle, but red muscle fibers are thinner than pale ones in average. 2. In the pectoralis major muscle, red muscle fibers are a little more than pale ones, but not significant. Diameters of red muscle fibers and that of pale ones are almost the same. 3. In the tibialis anterior muscle, red muscle fibers are more than pale ones, on the contrary in the gastrocunemius muscle, only 50% of muscle fibers are red. In both muscles red muscle fibers are a little thicker than pale ones in average. 4. Direct electrical stimulation on muscle does not change the stainability of the muscle to Sudan Bla k B. 5. The anterior tibialis muscle of the patient of dystrophia musculorus progressiva was exam ned by Sudan Black B staining.