SCOHOSIS is a permanent lateral de viation of the spine. It must be well differentiated from an uncertainty of attitude. It has often been observed in children under ten years that the spine forms a lateral curvature, because of inability to control their muscular action sufficiently to hold the still very flexible spine straight. Constant ob servation and repeated examinations prove that the uncertainty of attitude is accompanied by a convex curvature of the spine to the right or to the left. In a true scoliosis the spine always presents a. permanent curvature, and although the degree of curvature differs at tittles, being as a rule more pronounced during a period of fatigue, its character and localization remain the same. Cases of seoliosis where the spine presents a single curvature are termed right or left convex total scoliosis (Fig. 77). Opinions differ widely as to the frequency of this form of scoliosis. We have observed this form chiefly in children ranging front four to eight years. Later compensatory curvatures appear usually at the upper or lower (mil of the primary curvature. Sehulthess also reports similar observations. According to his investigations total scolioses amount to 15 per cent.; according to our own material to about 10 per cent. If the scoliosis is confined to one portion of the spine it is termed, in accordance with its localiza tion, lumbar, dorsal or cervical scoliosis; if the curvature embraces more than one division, a dorsolumbar or dorsocervical seoliosis.
As a rule there are one or two com pensatory curvatures directed toward the opposite side, just above or below the region of the spine that is affected by the main curvature. The most frequent. form of scoliosis belonging to this type is repro duced in Fig. 7S.
It is evident that curvature of the spine changes also the lateral outlines of the trunk—the side of the trunk correspond ing to the convexity projects while the opposite side recedes. Consequently the hip projects on the concave side and the layman terms the condition a high hip (Fig. 78). A change in the attitude of the shoulders generally accompanies the curvatures of the upper half of the spine.
As a rule the shoulder corresponding to the convex side is held higher than the one on the concave side (high shoulder, Fig. 78).
To these changes must be added, in every ease of scoliosis, deformities of the trunk which are produced by torsion.
Every lateral curvature of the spine is accompanied simultaneously by a rotation of the bodies of the vertebra. The vertebra generally rotates around its sagittal axis, the side corresponding to the convexity projecting backward. The rotation of the is less noticeable in the small vertebral bodies but is conspicuous in the long ribs attached to the vertebre. In scoliosis a projection of the ribs back ward takes place always on the convex side while the concave side of the thorax is twisted forward.
causes of scoliosis are of a very varied nature.
I. Congenital Scoliosis.—There are doubtless congenital scolioses produced either by constrained positions during the period of intra uterine life or caused by an asymmetrical arrangement of some of the Bohm's interesting investigations have quite recently drawn atten tion to the latter type. An X-ray picture of such congenital scoliosis is reproduced in Fig. 79. To this type belong also Garre's congenital scolioses which are caused by a seventh cervical rib. It is quite certain that congenital seolioses are much more frequent than has been esti mated heretofore. But Bobin's opinion —that most scolioses which develop in later life may be traced back to primary embryonic disturb ances—appears not to be well founded.
II. Rachitic Scoliosis.—In rachitic children scoliosis is frequently evoked during the first year by clumsy carrying and handling (Fig. SO). Such scolioses have to be dealt with very carefully. They soon develop to a marked degree and often present a marked rigidity during the second and third years. Nearly all advanced cases of scoliosis, especially all presenting simultaneously a kyphosis of the spine, called kyphosco Hoses, are caused by rachitic processes.