Youth and Sex

1. Changes in the Bodily Framework.-During this period the girl's skeleton not only grows remarkably in size, but is also the subject of well-marked alterations and development. Among the most evident changes are those which occur in the shape and inclination of the pelvis. During the years of childhood the female pelvis has a general resemblance to that of the male, but with the advent of puberty the vertical portion of the hip bones becomes expanded and altered in shape, it becomes more curved, and its inner surface looks less directly forward and more towards its fellow bone of the other side. The brim of the pelvis, which in the child is more or less heart-shaped, becomes a wide oval, and consequently the pelvic girdle gains considerably in width. The heads of the thigh bones not only actually, in consequence of growth, but also relatively, in consequence of change of shape in the pelvis, become more widely separated from each other than they are in childhood, and hence the gait and the manner of running alters greatly in the adult woman. At the same time the angle made by the junction of the spinal column with the back of the pelvis, known as the sacro-vertebral angle, becomes better marked, and this also contributes to the development of the characteristic female type.