Abstract
Using X-ray CT (computed tomography) images, the body composition of the right forearm in the proximal 1/3 and the distal 1/3 sections was studied in 104 humans (49 males, 55 females) . The total cross-sectional area, the each area of the subcutaneous fat, the connective tissue, the muscle and the bone were measured, then the percentage of the each area per the total area was calculated. Also the thickness of the subcutaneous fat was measured. And the changes due to sex, age and body type were investigated. The following results were obtained ; 1) Among the body compositions of the forearm in both sections, the muscle ratio was the largest, and the connective tissue ratio and the bone ratio which were almost equal to each other, and were the lowest. And the muscle ratio was higher in males than in females but the fat ratio was lower in males than in females. 2) Among the muscle composition in both sections, the flexor group was the largest, the dorsal extensor group was the second most and the radial extensor group was the smallest. But the radial extensor group was much decreased in the distal section. 3) The fat and connective tissue ratio increased and the muscle ratio decreased in fifties (remarkable in females) and sixties (remarkable in males) in both sections. 4) The fat and connective tissue ratio was the lowest in A type, the second most in C type and the higest in D type. The muscle ratio was the highest in A type, the second most in C type and the lowest in D type. 5) The subcutaneous fat was always thicker in females than in males, and thicker in the distal section than in the proximal section in most cases. 6) The subcutaneous fat at the radial site was generally thicker than the other sites and showed parallel relation with Rohrer Index. The thickness of the subcutaneous fat at the radial site in the distal 1/3 section was thought to be usefull as the index of the obesity.
