226 



HUMAN ANATOMY. 



Relations. In the neck the trachea is in front, the common carotids 

 on either side, and in the chest the pericardium, the left carotid, left sub- 

 clavian, the aorta, and the left bronchus are in front; the longus colli 

 muscle and the intercostal vessels and the vertebral column are behind. 

 The pleura covers it laterally, the descending portion of the arch of the 

 aorta lying on the left and' the vena azygos major on the right. 



Its structure consists of three coats: 

 Muscular coat, consisting of two layers, the longitudinal 

 and the circular, continuous with the inferior constrictor; 



FIG. 116. 



1, left hypochondriac region; 2, epigastric; 3, right hypochon- 

 driac; 4, left lumbar; 5, umbilical; 6, right lumbar; 7, left iliac; 

 8, hypogastric; 9, right iliac. 



Areolar or fibrous coat, connecting the two ; 



Mucous coat, covered with stratified pavement epithelium, 

 and having beneath it some non-striated muscular fibres, the mus- 

 cularis mucosse. It also contains numerous compound racemose 

 glands, the cesophageal glands. 



THE ABDOMEN. 



The abdomen, the largest cavity in the body, is bounded 

 in front and laterally by the abdominal muscles, the lower ribs, 

 the ilii, and above by the diaphragm, below by the brim of the 



