VBETEBEAL COLUMN 



51 



The spinous and transverse processes are subject to so much variation 

 that further description in this place is unnecessary. 



Nomenclature. Vertebra (from vertere, to turn) was originally 

 used for joints in general, and was applied by Celsus (A.D. 37) to the 

 segments of the spinal column. The Greeks employed spondylos or 

 stropheus (from strepho, to turn). The German name is die Wirbel ; 

 the French, la vertebrc. 



Muscular Attachments. The muscles attached to the vertebrae 

 are so numerous and vary so much in form and function in the 

 different regions of the column that a mere list of them, without 

 description and dissection, would be of little value. The student has 

 probably observed, when cleaning the skeleton, that the trunk-muscles 

 may be rudely classified in three groups. In the first group are those 

 which arise from vertebrae and are inserted in the head, the ribs, and 

 the extremities. In the second group are those which form the large 

 complex mass which occupies the furrow on each side of the row of 



FIG. 21. 



Neural Spine. 



Lamina. 



Transverse Process. 



Cephalic Articular Surface. 

 THORACIC VERTEBRA, DORSAL ASPECT. 



spinous processes. They arise from the sacrum and innominate bones, 

 and are directed toward the head and give off slips which have various 

 names and are inserted in the vertebrae of the different regions and 

 in the ribs. In the third group are the many small muscles which, 

 deeply placed and with limited range of motion, stretch from process 

 to process, and give rigidity to the column. 



Ossification. The typical vertebra is developed from five prin- 

 cipal centres of ossification, whereof three are primary centres, 

 namely, one for each lateral mass of the neural arch, one for the body 

 proper ; and two are secondary centres, namely, one for each epi- 



