To demonstrate the effect of physical irritancy(massages) on the skeletal muscles of immobilization ddY mice models induced by right side sciatic nerve neurectomy, the cross sectional histological profiles of the muscularis (M) gastrocnemius, M. tibialis cranialis and M. tibialis caudalis were observed after 28 days of treatment of physical irritancy with the changes of body weight thickness of hind limb and individual muscle weights. In addition, changes of demonstrated with diameter of individual muscle fiber and muscle fasciculata, and number of muscle fiber in each of three types of muscles located in the calf. The massages were used in this study as physical irritancy. The experimental groups were divided into five groups, 1) Sham-operated group(Sham), 2) Neurectomized but not physical irritated control group(Control), 3) Neurectomized and physical irritated at knee pint regions(T1), 4) Neurectomized and physical irritated at calf regions(T2), and 5) Neurectomized and physical irritated at achilles tendon regions(T3). The experimental animals were used 5 per groups. The changes of number or diameter of muscle fiber in each muscles were calculated using automated image analyzer. The results are as follow : Thickness(diameter) of muscle fiber of M. gastrocnemius, M. tibialis cranialis and M. tibialis cranialis in right side of hind limb were remarkedly decreased in Control, T1, T2 and T3 groups compared to that of Sham group. However, the thickness was significantly increased in physical irritated groups compared to that of Control group in followed order : T3<T1<T2. 2. Thickness(diameter) of muscle fasciculata of M. gastrocnemius, M. tibialis cranialis and M. tibialis caudalis in right side of hind limb were remarkedly decreased in Control, T1, T2 and T3 groups compared to that of Sham group. However, the thickness was significantly increased in physical irritated groups compared to that of Control group in followed order : T3<T1<T2. 3. Number of muscle fiber in muscle fasciculata of M. gastrocnemius, M. tibialis cranialis and M. tibialis caudalis in right side of hind limb were remarkedly decreased in Control, T1, 72 and T3 groups compared to that of Sham group. However, the number was significantly increased in physical irritated groups compared to that of Control group in followed order : T3<T1<T2.