I 

 6 THORAX AND ABDOMEN. 



9. The Ventral Cavity, as you perceive in the fig- 

 ure, does not reach up into the neck or head. . It 

 exists only in the trunk of the body, and is divided 

 into an upper story, B, the chest or thorax, and a 

 lower story, C, the abdomen, by a partition, d, which 

 forms the floor of the thorax and the ceiling of the ab- 

 domn. This partition is the diaphragm. How far in 

 your own body the chest-cavity extends you can find out 

 pretty accurately by beginning at the bottom of the neck 

 and feeling down along the middle of the front of your 

 trunk till you feel no more bones through the skin: 

 that level marks the bottom of the thorax. 



10. Contents of the Thorax. On Fig. i you will also see 

 that the mouth, o, and the nose, /, join behind, and that 

 from the place of meeting two tubes run down the neck. 

 The front one of these tubes is the windpipe or trachea; 

 after entering the thorax it ends in the lungs, I. In the 

 thorax is also placed the heart, h. 



11. Contents of the Abdomen. The second of the tubes 

 above referred to is the gullet or oesophagus. It runs right 

 on through the chest and diaphragm into the abdomen, 

 and there opens into the stomach, f. 



The air we take in when breathing goes along the 

 windpipe to the lungs, but no further: the food and 

 drink which we swallow take a longer road along the 

 gullet to the stomach. 



In addition to the stomach, the liver, the intestines or 

 bowels, and the kidneys, k, lie in the abdomen. 



9. Where is the ventral cavity ? Name its divisions. The parti- 

 tion. How can you trace the chest or thorax in your own body ? 



10. Name contents of thorax. 



11. What is the course of the gullet? Its use ? Use of the wind- 

 pipe ? Name the organs which lie in the abdomen. 



