Vitality Supreme

The curves in the human spine are characteristic, illustrating in another way the modification of the vertebral column that has been made necessary by the erect position. The new-born baby has a backbone that is almost straight, and in this respect it bears a strong resemblance to that of many of the lower animals. The typical human curves, however, begin to take form as soon as the child learns to sit up, and they become more marked as he learns to walk and run. These curves are essential to maintaining the balance of the body in the erect position. There are really three curves in the human backbone, the cervical curve being convex, the dorsal concave, and the lumbar convex, when each is regarded from the forward aspect. If we consider the sacrum and coccyx, there is really a fourth curve, this being concave, although in animals generally the coccyx curves backwards and is extended to form the tail. In some of the lower animals the spine is nearly straight, while in some cases it virtually forms a complete arch from one end to the other. These curves of the spine are generally more marked in the civilized white races than among the black and savage races, and as a rule they are more pronounced among women than among men. For instance, in comparing the sexes we find that in a woman the lumbar curve is more marked and extends slightly higher than in a man, and that the broad sacrum characteristic of the human race is even wider, being thus adapted to the broader hips and wider pelvic cavity of the child- bearing sex.