Spasticity resulting from disorders of the central nervous system represented on of the most disabling motor disorders. The methods to be used for quantifying spasticity were many ways, but it was difficult to measure it correctly. Therefore I wished to introduce the new concepts of method for quantifying spasticity to be present in the upper extremity using pendulum test in this study. The formula of relaxation index in the upper extremity was defined form calculating the amplitude ratio of tweenty-eight normal persons(male: fifteen, female: thirteen) with measuring swing angles from ㇋₀ to ㇋₅ respectively using electrogoniometer. And then the relaxation index of the patients was calculated through that formula.

The results were that the relaxation index was a simple and good index for quantifying spasticity, and the second relaxation index was the most appropriate index to evaluate spasticity in the upper extremity.