THE (ESOPHAGUS 



1239 



The circular fibres are continuous above with the Inferior constrictor of the pharynx; their 

 direction is transverse at the upper and lower parts of the tube, but oblique in the intermediate 

 part. Below, the circular fibres pass into the circular and oblique fibres of the stomach. 



The muscle fibres in the upper part of the oesophagus are of a red color, and consist chieflv of 

 the striped variety, but below they consist for the most part of involuntary muscular fibres. 



The submucous coat (tela s&bmucosa) connects loosely the mucous and muscular coats. 



The mucous coat (tunica mucosa) is thick, of a reddish color above and pale below. It is 

 disposed in longitudinal folds, which disappear on distention of the tube. Its surface is studded 

 with minute papilla?, and is covered throughout with a thick layer of stratified pavement epi- 

 thelium. Beneath the mucous membrane, between it and 

 the submucous coat, is a layer of longitudinally arranged 

 nonstriped muscle tissue. This is the muscularis mucosae 

 (lamina muscularis mucosae). At the commencement of the 

 oesophagus it is absent, or only represented by a few scattered 

 bundles; lower down it forms a considerable stratum. 



The oesophageal glands are small compound racemose 

 glands of the mucous type; they are lodged in the submucous 

 tissue and each opens upon the mucous surface by a long 

 excretory duct. 



Vessels and Nerves. The larger vessels are in the 

 submucosa and send branches to the mucosa and muscularis. 

 The arteries supplying the oesophagus are derived from the 

 inferior thyroid branch of the thyroid axis of the subclavian, 

 from the descending thoracic aorta and the bronchial arte- 

 ries, and from the gastric branch of the cceliac axis, and from 

 the left inferior phrenic of the abdominal aorta. They have 

 for the most part a longitudinal direction. The veins are 

 gathered into a plexus on the outer surface of the oesopha- 

 gus. This plexus receives the venous blood from the walls 

 of the tube. From the lower portion of the plexus branches 

 go to the coronary vein of the stomach. Higher up branches 

 go to the azygos veins and thyroid veins. In this manner 

 a communication is opened between the portal veins and the 

 systemic veins. 



The lymphatics drain into the inferior deep cervical nodes 

 and the nodes of the posterior mediastinum. 



The nerves are derived from the vagus and from the 

 sympathetic; they form a plexus in which are groups of 

 ganglion cells between the two layers of the muscular coat. 

 From this fibres pass to supply the muscle, and others go to 

 the submucous tissue to form a secondary plexus. It is 

 usual to regard the plexus as consisting of two parts, an 

 anterior oesophageal plexus, derived from the left vagus, 

 and a posterior oesophageal plexus, derived from the right 

 vagus. These two plexuses are in the posterior mediasti- 

 num ; they communicate with each other and contain sym- 

 pathetic fibres. 



Applied Anatomy . The relations of the oesophagus are of considerable practical interest 

 to the surgeon, as he is frequently required, in cases of stricture of this tube, to dilate the canal 

 by a bougie, when it is of importance that the direction of the oesophagus and its relations to 

 surrounding parts should be remembered. In cases of malignant disease of the oesophagus, 

 where its tissues have become softened from infiltration of the morbid deposit, the greatest 

 care is requisite in directing the bougie through the strictured part, as a false passage may easily 

 be made, and the instrument may pass into the mediastinum, or into one or the other pleural 

 cavity, or even into the pericardium. 



One should also remember that obstruction of the oesophagus, and consequent symptoms of 

 stricture, are occasionally produced by aneurism of some part of the aorta pressing upon the 

 tube. In such a case the passage of a bougie could only hasten the fatal issue. 



In passing a bougie the left forefinger should be introduced into the mouth and the epiglottis 

 felt for, care being taken not to throw the head too far backward. The bougie is then to be 

 passed beyond the finger until it touches the posterior wall of the pharynx. The patient is 

 now asked to swallow, and at the moment of swallowing the bougie is passed gently down- 

 ward, all violence being carefully avoided. 



It occasionally happens that a foreign body becomes impacted in the oesophagus and can 

 neither be brought upward nor moved downward. When all ordinary means for its removal 

 have failed, and the body is lodged above the lower one-third of the gullet, external aesopha- 



FIG. 956. Accessory muscle slips 

 between the oesophagus and pleura, 

 and oesophagus and trachea. (From 

 a preparation in the Museum of the 

 Royal College of Surgeons of England.) 



