THE ALIMENTARY CANAL 177 



air we breathe crosses that of the food we swallow. The 

 larynx, which is ventral to the lower part of the pharynx 

 and under the tongue, belongs to the respiratory tract 

 exclusively. The breath comes and goes through the 

 larynx and the food enters the esophagus. 



This is a tube leading to the stomach. It runs down 

 behind the trachea or windpipe until the fork in that 

 passage is reached; then the esophagus continues behind 

 the heart and pierces the diaphragm. Immediately 

 below this partition it expands into the stomach. This 

 is a sac lying mainly to the left of the middle line and 

 higher up than is popularly supposed. It is within the 

 ribs as viewed from the side and could be reached from 

 in front by an incision just below the end of the breast 

 bone. The spleen is in the limited space to the left of 

 the stomach while the much larger space between it 

 and the right ribs is filled by the great mass of the 

 liver. 



The shape of the stomach varies according to cir- 

 cumstances but it may be said to have somewhat the 

 form of a pear, the small end being directed downward 

 and to the right. The small intestine takes its departure 

 from this tapering extremity. A line drawn from the 

 place where the esophagus enters along the upper border 

 to the place where the intestine leaves is said to follow 

 the lesser curvature. The much longer line connecting 

 the same points but following the lower border defines 

 the greater curvature. The opening from the esophagus 

 to the cavity of the stomach is the cardia; that from the 

 stomach to the intestine is the pylorus. 



The small intestine is the longest division of the canal, 

 having a course of about 20 feet. It is coiled in a 

 manner which defies description and it ends by joining 

 the colon near the right hip bone. Its first turn after 

 leaving the stomach is called the duodenum and it 

 encircles the head of the pancreas. Beyond the duo- 

 denum the small intestine is rather vaguely divided into 

 two sections, the jejunum and the ileum. The words 

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