Motor System — Muscles and Skeleton 



109 



Inspection of the vertebral processes gives an experienced anato- 

 mist much information concerning the disposition of muscles along the 

 column. The length of its spines and processes is an indication of the 

 extent to which the vertebra is used for attachment of muscles. The 



INTERVERTEBRAL 

 FIBROCARTILAGE . 



. Coccygeal. 



Fin. 107. The human vertebral column 

 viewed from the left side. (After Sobotta. 

 Courtesy, Neal and Rand: "Chordate 

 Anatomy," Philadelphia, The Blakiston 

 Company.) 



leverage or "pull" which a muscle may exert in relation to the fulcrums, 

 which are the intervertebral joints, varies with the length of the process 

 — i.e., with the distance from the muscle's point of attachment to the 

 axis of the centrum. The thickness of a process indicates the intensity 

 of the strain which it must sustain. The slope of the process in relation 



