66 



SPECIAL ANATOMY OF THE SKELETON 



FIG. 38. Lateral view of the vertebral column. 



The Vertebral Column as a Whole. 



The vertebral column (columna verte- 

 bralis), formed by the interarticulation of 

 the vertebrae, is situated in the median line, 

 in the posterior part of the trunk; its average 

 length is about two feet two or three inches 

 (65 to 67.5 cm.), measuring along the curved 

 anterior surface of the column. Of this 

 length, the cervical part measures about 

 five, the thoracic about eleven, the lumbar 

 about seven inches, and the sacrum and 

 coccyx the remainder. The female column 

 is about one inch less than that of the male. 



Viewed laterally (Fig. 38), the spinal 

 column presents several curves which cor- 

 respond to the different regions of the 

 column, and are called cervical, thoracic, 

 lumbar, and pelvic. The cervical curve 

 commences at the apex of the odontoid 

 process, and terminates at the middle of 

 the second thoracic vertebra; it is convex 

 in front, and is the least marked of all 

 the curves. The thoracic curve, which is 

 concave forward, commences at the middle 

 of the second, and terminates at the middle 

 of the twelfth thoracic vertebra. Its most 

 prominent point behind corresponds to the 

 spine of the seventh thoracic vertebra. The 

 lumbar curve commences at the middle of 

 the last thoracic vertebra, and terminates 

 at the sacrovertebral angle. It is convex 

 anteriorly; the convexity of the lower three 

 vertebrae being much greater than that of 

 the upper two. The pelvic curve com- 

 mences at the sacrovertebral articulation 

 and terminates at the point of the coccyx. 

 It is concave anteriorly. The thoracic and 

 pelvic curves are the primary curves, and 

 begin to be formed at an early period of 

 fetal life, and are due to the shape of the 

 bodies of the vertebrae. The cervical and 

 lumbar curves are compensatory or sec- 

 ondary, and are developed after birth in 

 order to maintain the erect position. They 

 are due mainly to the shape of the in- 

 tervertebral disks. Not uncommonly the 

 thoracic portion of the vertebral column 

 even in healthy persons deviates toward 

 the right. This is due to the position of 

 the heart and of the arch of the aorta. 



The movable part of the vertebral column 

 presents for examination an anterior, a pos- 

 terior, and two lateral surfaces; a base, a 

 summit, and the vertebral canal. 



