日本人のcarpal angleについて

Abstract

The “carpal angle” was first described by Jerzy Kosowicz in 1962 with reference to gonadal dysgenesis. He defined the carpal angle as the angle resulting from the intersection of two lines, one tangent to the proximal edges of the lunate and scaphoid and another to those of the lunate and triquetrium. Kosowicz observed the patients with gonadal dysgenesis showed a lesser carpal angle compared with the normal individuals and named the carpal angle of 117° or less the “positive carpal sign”. Kosowicz did not published the age, sex, or race of the individual in his normal population. On the basis of 184 males and 247 females aged 4 to 88 years Takahashi (1976) reported that no significant differences were found in the mean values in assoication with age, sex or between the right and left hands and that the mean value of the carpal angle in normal Japanese was 126.0° and the incidence of the positive carpal sign was 16.5% in the males and 20.0% in the females. While, on the basis of 928 Americans (231 white males, 231 white females, 230 black males and 236 black females) aged 48 months to 83 years, Harper, Poznanski and Garn (1974) found that the carpal angle was greater in blacks than in whites, it increased with age during childhood and at most ages was slightly greater in males than in females. Besides, on the basis of 10 normal women bolunteers they found that the carpal angle was much greater in ulnar than in radial deviation and was slightly larger on the left than on the right. It is the purpose of the present paper to analyse the effects of these factors on the carpal angle in normal Japanese. As for to the age effect to the carpal angle, especially, the skeletal maturation of hand and wrist bones was considered. The materials consisted of 58 students volunteers (31 males and 27 females), 490 boys and 429 girls aged 1 to 18 years and 51 pairs (24 male and 27 female pairs) of monozygotic twins aged 17/18 years. The following results were obtained;1) The carpal angle shows no significant differences in the mean values in association with sex and between the right and left hands (p=0.01).2) Significant effects of positioning are found in the carpal angle (p=0.01). The carpal angle is lesser (12.3°) in abduction and greater (16.4°) in adduction than in neutral position.3) The age change of the carpal angle is almost similar in both sexes in their patterns, preceding about 2 years in the females than in the males. This trend appears to be more apparent in the skeletal age change than in the chronological one of the carpal angle. Furthermore, in the change of the carpal angle with the skeletal maturation of the scaphoid, lunate and triquetrium the curves for both males and females are coincident each other not only in the pattern but also in timing.4) The carpal angle is significantly greater (about 5°) in the unmatured group than in the matured one as for the scaphoid, lunate and triquetrium (p=0.01).5) A significant correlation is found between the right and left hands and between pairs of monozygotic twins (p=0.01) in the carpal angle. This fact seems to show a hereditality of the carpal angle.6) The carpal angel is slightly lesser in Japanese than in American whites and blacks. The mean values of the carapal angle is 122.8° in the males and 122.3° in the females for normal skeletally adult Japanese.7) Therefore, the incidence of the positive carpal sign is generally higher in the females (25.5%) than in the males (16.5%), in the left than in the right and in Japanese than in whites.According to these facts, it seems to be concluded that various factors, especially position, age and race, can not be neglected to discuss the carpal angle with reference to gonadal dysgenesis.