366 PRACTICAL ANATOMY. 



sympathetic. Two glandular organs the tonsils are 

 placed on either side, between the pillars of the fauces. 

 Their bases are applied opposite " to the course of the 

 great vessels, an important fact to remember in opera- 

 tions on these structures. 



THE (ESOPHAGUS. 



The musculo-mernbranous tube, which leads from 

 the pharynx into the stomach, is about nine inches long, 

 and extends from the fifth cervical to about the ninth 

 dorsal vertebra. It passes down in front of the bodies 

 of the vertebrae, through the posterior mediastinum and 

 through the cesophageal opening of the diaphragm, and 

 enters the cardiac end of the stomach. It has three 

 coats, muscular, fibrous, and mucous. The muscular 

 or outer is formed by longitudinal and circular fibres ; 

 the fibrous coat consists of loose cellular connective 

 tissue ; the mucous coat is thrown into longitudinal 

 rugae, and is covered with squamous epithelium. The 

 oesophagus is in relation in the neck with the trachea 

 anteriorly, and laterally with the great vessels. In the 

 thorax it descends in the posterior mediastinum, having 

 in front the structures of the root of the lungs, and, lower 

 down, the pericardium. It is covered laterally by the 

 pleurae. The pneumogastrics descend upon it, the right 

 behind, the left in front. The continuation of the ali- 

 mentary tract is situated in the abdominal cavity. 



