THE SPINE. 83 



result in confusion. When the skull of a negro is 

 viewed in profile, it is observed that the superior maxil- 

 lary bones project, that the teeth are thrust obliquely 

 forward, and that the malar bones also project for- 

 ward. If a line is drawn in such a skull from the 

 glabella to the mental process, it will fall considerably 

 behind the canine teeth. Such a skull is called prog- 

 nathous, and occurs largely in the natives of Africa and 

 Oceanica. An orthognathous skull is one in which the 

 facial structures do not project beyond a vertical line 

 dropped from the glabella ; in such a skull the teeth are 

 generally fixed in a vertical position. The " Caucasian " 

 race of Blumenbach are mostly orthognathous. 



Many other details of great interest are beyond the 

 purposes of this book, and the reader is referred to the 

 numerous treatises on this subject. 



THE SPINE. 



The spine, or vertebral column, consists of twenty- 

 six bones, including the sacrum and coccyx. The ver- 

 tebrae, twenty-four in number, are piled one upon 

 another, forming a strong, flexuous, tapering column 

 which rests on the base of the sacrum. The vertebrae 

 are divided into three groups, superior or cervical, 

 middle or dorsal, and inferior or lumbar. Each vertebra 

 presents for examination a body, two pedicles, two 

 laminae, a spinous process, two transverse processes, and 

 two pairs of articular surfaces. The body is in front; it 

 is a cylindroid mass of bone, and forms, with the ver- 

 tebras above and below, the pillar of support to the head 

 and upper extremities. Its superior and inferior sur- 

 faces are articular, slightly concave, and elevated at the 

 circumference into a rim or lip. In front and at the 



