Abstract
Muscle weight, number of muscle fibers and size of the muscle fibers were measured in foot muscles of adult crab-eating monkey (7.2 kg, male) and the results were compared with those obtained in human hand and foot muscles and monkey hand muscles previously by the same method. Histological specimens were embedded in celloidin and stained by H. E. The following results were obtained. 1) Total muscle weight and total number of muscle fibers in hand and foot of monkey and man followed an ascending order of monkey hand<monkey foot<human hand<human foot. No larger values than those of M. tibialis anterior were obtained in monkeys. On comparison with proper foot muscles after eliminating flexors and extensors of the foot, however, muscle weight was heavier in foot than in hand in monkey, but equal between hand and foot in man. Number of muscle fibers was equal between hand and foot in monkey, but smaller in foot than in hand in man. 2) In monkey foot, M, adductor hallucis and corresponding muscles were developed, with large diameter of muscle fibers. The opponent movement between the thumb and other fingers is probably active. 3) In monkey hand, muscles acting on concentration of fingers are developed, with muscle fibers of large diameter. 4) In human foot, muscles participating in arch formation in the longitudinal and transverse direction are well developed. In muscles participating longitudinal arch formation, the diameter of the fibers showed remarkable development. This probably represents development of muscles related to upright standing and walking. 5) In human hand, M. adductor pollicis and corresponding muscles showed development, with large number of muscle fibers. The diameter of the muscle fibers, however, are generally middle-sized or small, probably as the result of adaptation to fine movement.
