LYMPHATICS AND THORACIC DUCTS. 485 



interrupted by small tendons ( \y to -Jg- of an incli long) like the 

 fibres of the rectus abdominis muscle. 



The internal layer of circular fibres is continuous above with the and internal 

 fibres of the pharynx ; they are more oblique at the middle than aSf* 

 at either end of the oesophagus. 



The areolar or submucous layer is situate between the muscular Fibrous 

 and mucous coats, and attaches the one to the other loosely. layer - 



The mucous coat will be seen on cutting open the tube ; it is Mucous 

 reddish in colour above but pale below, and is very loosely con- coat ' 

 nected with the muscular coat, so that it is thrown into longitudinal 

 folds when the oesophagus is contracted. The surface is studded Papillae and 

 with minute papillae, which are, however, concealed by the thick, ep 

 laminated, scaly epithelium. 



Some compound glands (cesophageal) are scattered along the tube, Some 

 and are most numerous at the lower end of the gullet. 



LYMPHATICS OF THE THORAX. In the thorax are lymphatic Lymphatics 

 vessels of the w r all and the viscera, which enter collections of 

 glands, and end in one or other of the lymphatic ducts. Besides 

 these, the large thoracic duct traverses the thorax in its course from 

 the abdomen to the neck. 



LYMPHATIC GLANDS. Along the course of the internal mammary sternal 

 artery lies a chain of sternal glands, which receive lymphatics from s lands - 

 the upper part of the abdominal wall, the front of the chest, the 

 mamma, and the fore part of the diaphragm. 



On each side of the spine, near the heads of the ribs, as well as intercostal, 

 between the intercostal muscles, is placed a group of intercostal 

 glands for the reception of the lymphatics of the posterior wall of 

 the thorax. 



Three or four anterior mediastinal glands lie in the fore part of Anterior 



.i..-, , , i i j_- / .1 mediastinal. 



the mterpleural space, and receive lymphatics from the upper sur- 

 face of the liver and the diaphragm. 



Numerous bronchial glands are situate at the division of the Bronchial, 

 trachea, and along the bronchi ; through them the lymphatics of 

 the lung pass. 



Along the side of the aorta and oesophagus is a chain of posterior Posterior 



j. Tr i , 7 -,-T .. T i ^ i i ,. ,. 7-t mediastinal. 



mediastinal glands, which are joined by the lymphatics ot the oeso- 

 phagus, and hinder parts of the pericardium and diaphragm. 



Along the front and lower border of the arch of the aorta are the Superior 

 superior mediastinal or cardiac glands, which receive the lymphatics m ' 

 of the heart, the pericardium, and the thymus. 



The THORACIC DUCT (fig. 174 and fig. 1 75, *) is the main channel by Thoracic 

 which the lymph of the lower half of the body, and of the left side 

 of the upper half of the body, as well as the chyle from the intestines, 

 is conveyed into the blood. The duct begins in the abdomen in an begins in 

 enlargement (receptaculum chyli ; p. 371), and ends in the veins of m^and" 

 the left side of the neck. It is from fifteen to eighteen inches in ends in 

 length, and is contained in the thorax, except at its origin and 

 termination. It has the following course and relations : 



Entering the cavity through the same opening as the aorta, the Relations 

 duct ascends on the right side of that vessel as high as the arch, 



