508 ORGANS OF DIGESTION. 



nously, from the posterior face of the cricoid cartilage, and the 

 other two, one on each side, from the inferior constrictor of 

 the pharynx. These fasciculi descend for an inch or two be- 

 fore they spread out into a uniform membrane. The internal 

 muscular lamina consists in circular fibres, which may be con- 

 sidered as a continuation of the lower margin of the inferior 

 constrictor of the pharynx, and are either horizontal or slightly 

 spiral; they are rather deficient on the fore part of the ceso- 

 phagus for an inch at its superior extremity. Individually, 

 their length is short of the circumference of the ossophagus. 



_ r 



The cellular coat is next in order, and serves to unite the 

 muscular and the mucous together. It adheres much more 

 closely to the latter than it does to the former, has no adipose 

 matter in it, but is found to be abundantly furnished, more par- 

 ticularly towards its upper end, with small muciparous glands; 

 it also serves to transmit the blood vessels through the struc- 

 ture of the oesophagus. 



The mucous coat of the oesophagus is the most internal; in 

 the undistended state it always presents many longitudinal 

 folds, going from one end to the other, but sometimes blending 

 with each other, owing to the contraction of the circular mus- 

 cular fibres. When suspended in water its fine villous ap- 

 pearance is very perceptible, as well as the mucous lacunae or 

 glands which open upon its internal surface. As it is a conti- 

 nuation of the mucous membrane of the pharynx, it has the 

 same general appearance, but is rather whiter. Its internal 

 surface is also covered by a delicate epidermis, which ceases 

 at the cardiac orifice of the stomach, and may be raised in 

 shreds by maceration and by boiling; in some pathological 

 conditions this epidermis becomes very distinct by acquiring 

 more thickness and solidity, than what belong to its healthy 

 state. 



The arteries of the oesophagus are derived from the inferior 

 thyroidal, from the thoracic aorta, and from the gastric. Its 

 nerves come principally from the pneumogastric. 



END OF VOL. I. 



