CHAPTER III 



BONES AKD ARTICULATIONS OF THE 

 SPINAL COLUMN AND TRUNK 



The bones of the spinal column are 

 twenty-six in number. They are irregular 

 and are arranged as follows, from above 

 downward: 



24 separate vertebrae 



i sacrum, 

 i coccyx. 



7 cervical in the neck. 



12 thoracic in the back. 



5 lumbar in the loins. 



in the pelvis. 



A vertebra consists of a _body and an 

 arch, joined, together to form a ring of 

 Done with a space enclosed called the 

 vertebraTforamen , which is occupied by the 

 spinal cord. Trie bodies are composed of 

 spongy bone, placed one above the other 

 and held together by discs of fibrocartilage 

 between them. In this way the solid and 

 flexible portion of the spine is constructed. 



The arch consists of two roots next to the 

 body, antt two larkiriti which meet at the 

 l)ack. ' There are seven processes on the 

 arch of each vertebra tour articular (two 

 to form joints with the bone above, two 

 for the bone below); two transverse (pro- 

 j'ecting from the sides), and one spinou^ 

 which projects backward. The row of 

 spinous processes is felt by passing the finger 

 down the back in the median line; that of 

 the seventh vertebra is easily seen, and 

 this bone is called the vertebra prominent. 



39 



FIG. 31. VERTEBRAL 

 COLUMN, LATERAL ASPECT. 



1-7, Cervical vertebrae; 

 8-19, dorsal vertebras; 20- 

 24, lumbar vertebrae; A, A, 

 spinous processes; B, B, 

 articular facets of trans- 

 verse processes of first ten 

 dorsal vertebrae; C, auricu- 

 lar surface of sacrum; D, 

 D, foramina in transverse 

 processes of cervical verte- 

 brae (Sappey.) 



