18 



ANATOMY FOR NURSES 



[Chap. II 



them through the middle line from before backwards, we find the 

 trunk and head are divided by the bones of the spine into dorsal 

 and ventral cavities, and not into upper and lower. (See Fig. 3.) 



1. Dorsal cavity. — The dorsal or back cavity is a complete 

 bony cavity, and is formed by the bones of the skull, and the 

 vertebrae (bones of the spine). It may be subdivided into: — 



a. The cranial cavity. — This cavity contains the brain. 

 6. The spinal canal. — This canal contains the spinal cord, which 

 is continuous wMth the brain. 



2. Ventral cavity. — The ventral or front cavity is not a com- 

 plete bony cavity, part of its walls being formed of muscular and 



Fig. 4. — Position of the Thoracic and Abdominal Organs (Front View). 



(Morrow.) 



other tissue ; it is much larger than the dorsal cavity, and may 

 be subdivided into : — 



