592 BLOODVESSELS OF THE ALIMENTARY CANAL, BY C. TOLDT. 



usually join by means of an anastomotic ring with the venous 

 plexuses of the mucous membrane. 



Mucous MEMBRANE OF THE PHARYNX. 



The upper parts of the pharynx receive their supply of blood 

 through the pharyngo-palatine and spheno- palatine branches of 

 the internal maxillary artery, whilst the middle and lower parts 

 are supplied directly from the external carotid by the ascending 

 pharyngeal and palatine arteries. The terminal branches of 

 these vessels run obliquely towards the surface of the sub- 

 mucous layer, where they ramify, ultimately dividing into fine 

 branches that run immediately beneath the epithelial layer of 

 the mucous membrane. Capillaries, having a diameter of O'OOG 

 of a millimeter, are given off from these vessels, which form 

 simple loops in the serially arranged papillae. There is scarcely 

 any region where papillse are found in which the vascular loops 

 present so much uniformity as here. The descending portions 

 of the loops unite into veins that quickly acquire a consi- 

 derable size, and these vessels communicate by numerous anas- 

 tomoses, and run for the most part in the direction of the long 

 axis of the pharynx, so as to form a plexus with elongated 

 meshes. Sooner or later 'the larger venous trunks join the 

 veins of the subjacent glandular or muscular layer. The ex- 

 cretory ducts of the mucous glands are surrounded at their 

 orifices with circularly arranged papillary loops. 



Mucous MEMBRANE OF THE (ESOPHAGUS. 



The vascular plexus of the mucous membrane of the osso- 

 phagus, derived from the oesophageal arteries, and from small 

 branches of the inferior thyroid and bronchial arteries, is 

 extremely close. "The larger vessels run longitudinally in the 

 submucous layer, communicating from time to time by trans- 

 verse anastomoses (fig. 114, a). The smaller branches reach 

 the mucous membrane obliquely, and then usually become 

 longitudinal and very sinuous in their course ; they also form a 

 plexus with elongated meshes (fig. 114, 6), from which the 

 capillary loops, destined for the most superficial layer, arise 



