l6l2 



H I. MAN ANATOMY. 



Lymph- 

 node in 



appearing in the continuation of the elastic lamina of the pharynx. At the upper end 

 only slightly developed, the muscularis mucosae becomes more robust until in the 

 lower portion of the oesophagus it is conspicuous. 



The submucous coat, between the mucous and muscular layers, although consid- 

 erable, is not dense, and therefore allows free motion of the former upon the latter, 

 as well as the formation and effacement of folds. It is continuous with the pharyn- 

 geal fascia above. 



The ozsophageal glands are of two kinds, the ordinary mucous, situated within 

 the submucous coat and scattered throughout the length of the tube, and special 

 glands within the tunica propria limited to the two ends of the oesophagus. The 

 last mentioned correspond in structure to those found at the cardiac orifice of the 

 stomach ; they are therefore known as the upper and lower cardiac ocsophageal glands 

 (J. Schaffer). 



The usual secretory structures are small tubo-alveolar mucous glands in which 

 mucus-producing cells are alone present, crescents of serous elements being absent. 

 The ducts are commonly somewhat tortuous, and often present dilatations or ampullae; 



the smaller tubes are clothed with simple 

 columnar epithelium. In the larger the 

 epithelium may be stratified, and near the 

 free surface assume a squamous character. 

 The cardiac glands at the lower end 

 of the oesophagus are continuations of 

 those situated about the entrance of the 

 gullet into the stomach, in connection with 

 which organ they are more fully described 

 (page 1624). They form oval or pyrami- 

 dal groups of branched tubular glands, the 

 bases of which lie against the muscularis 

 mucosae, the narrow parts being directed 

 towards the free surface onto which their 

 wavy or tortuous ducts open. The upper 

 cardiac glands form, according to Schaf- 

 fer, 1 a constant, though variable, group 

 around the superior end of the oesophagus. 

 Lymphatic tissue occurs within the 

 mucosa of the oesophagus as more or less 

 distinct aggregations. Sometimes these 

 are in the form of small diffuse areas of 

 infiltration around the ducts of the mucous glands ; in other places, especially towards 

 the lower end, distinct lymph-nodules are present (Fig. 1364). 



The muscular coat consists of an inner circular and an outer longitudinal layer, 

 although the disposition of the individual bundles is often irregular and oblique, and 

 above somewhat intermingled. In the upper one-fifth of the tube the muscular 

 tissue tourists entirely of striped fibres, the circular ones being continuous with the 

 similarly disposed fibres of the inferior constrictor of the pharynx. The longitudinal 

 fibres arise troin a tendon attached to the median ridge of the cricoid cartilage and 

 to the fascia covering the posterior crico-arytenoid muscles, whence they descend 

 to embrace the- gullet. They are few at the top behind, but lower down tlie circular 

 and longitudinal layers are distinct and symmetrically disposed. Towards the middle 

 of the oesophagus the muscular coat includes both the striated and non-striated form 

 of ti->Mie. the involuntary variety gradually predominating until in the lower two-fifths 

 it alone is present. 



The fibrous coot is poorly developed above the diaphragm, consisting of the 

 areolar ti^ue u hit h . ..nnerts the gullet to the surrounding structures. After piercing 

 the diaphragm, the peritoneal investment contributes a limited serous tunic which from 

 this point on is \\ell represented. 



Vessels. The art,-ri,s are links in the chain running the whole length of the 

 alimentary .anal. The highest are from the inferior thyroids, Succeeded by those 



y.\\r Hist.. ],.-!< in. ns< li. ( )r-ane, B.I. vi 



Muse u la 

 tissue 



Section of mucous membrane of oesophagus, showing 

 lymph-node. X 55. 



