DIGESTIVE ORGANS STOMACH. 519 



cles. The two internal pterygoids raise it; the two external ptery golds 

 stretch it transversely ; the two palato-pharyngei Qvpharyngo-staphylini, 

 and the two constrictores isthmi faucium or glosso-staphylini carry it 

 downwards. The last four muscles form the pillars of the fauces; 

 the first two the posterior pillars ; and the last two the anterior ; be- 

 tween which are situate the tonsil glands or amygdalae, which are not 

 really glandular, but composed of a congeries of mucous follicles. 



2. The pharynx and oesophagus constitute a muscular canal, which 

 forms the medium of communication between the mouth and stomach, 

 and conveys the food from the former of these cavities to the latter. 



The pharynx has the shape of an irregular funnel, the larger open- 

 ing of the funnel looking towards the mouth and nose ; the under and 

 smaller end terminating in the oesophagus. Into its upper part, the 

 nasal fossae, Eustachian tubes, mouth, larynx, and oesophagus open. 

 It is inservient to useful purposes in the production of voice, respira- 

 tion, audition, and digestion ; and extends from the basilary process of 

 the occipital bone, to which it is attached, as far as the middle part of 

 the neck. Its transverse dimensions are determined by the os hyoides, 

 larynx, and pterygo-maxillary apparatus, to which it is attached. It 

 is lined by a mucous membrane, less red than that which lines the 

 mouth, but more so than that of the cesophagus, and the rest of the 

 digestive tube ; and it is remarkable for the developement of its veins, 

 which form a very distinct network. Around this is the muscular layer, 

 the circular fibres of which are often divided into three muscles supe- 

 rior, middle, and inferior constrictors. The longitudinal fibres form 

 part of the stylo-pharyngei and palato-pharyngei muscles. The pharynx 

 is raised by the action of the last two muscles, as well as by all those 

 that are situate between the lower jaw and os hyoides, which cannot 

 raise the latter without, at the same time, raising the larynx and pha- 

 rynx. These muscles are : mylo-hyoideus, genio-hyoideus, and the 

 anterior belly of the digastricus. 



The oesophagus is a continuation of the pharynx ; and extends to the 

 stomach, where it terminates. Its shape is cylindrical, and it is con- 

 nected with the surrounding parts by loose and extensible areolar tissue, 

 which yields readily to its movements. On entering the abdomen, it 

 passes between the pillars of the diaphragm, with which it is intimately 

 united. The mucous membrane lining it is pale, thin, and smooth ; 

 forming longitudinal folds, well adapted for favouring the dilatation of 

 the canal. Above, it is confounded with that of the pharynx ; but 

 below, it forms several digitations, terminated by a fringed extremity, 

 which is free in the cavity of the stomach. It is well supplied with 

 mucous follicles. The muscular coat is thick ; its texture is denser 

 than that of the pharynx, and cannot, like it, be separated into dis- 

 tinct muscles, but consists of circular and longitudinal fibres, the former 

 of which are more internal, and very numerous, the latter external and 

 less numerous. Fig. 217 exhibits the situation and arrangement of the 

 two sets of fibres. 



3. The stomach is situate in the cavity of the abdomen, and is the 

 most dilated portion of the digestive tube. It occupies the epigastric 

 region, and a part of the left hypochondre. Its shape has been com- 



