【名词&注释】
肩关节周围炎(scapulohumeral periarthritis)、不稳定(unstable)、儿童股骨头缺血性坏死(legg-calve-perthes disease)、肩关节前脱位(anterior dislocation of shoulder joint)、男女比例(proportion of male and female)、不完全(incomplete)
[单选题]儿童股骨头缺血性坏死多发生于____,男女比例(proportion of male and female)为____( )
A. 4~9岁,4:1
B. 6~9岁,3:1
C. 3~9岁,2:1
D. 4~9岁,1:1
E. 以上都不是