1112 



THE DIGESTIVE SYSTEM. 



The philtrum 



Raphe of palate 



Pharyngo- 

 latine arch 



niinora, and are distributed to the palatine tonsil and palate, and anastomose with branches of the 

 ascending pharyngeal artery. 



The largest branch, greater palatine artery, emerges through the foramen palatinum majus, 

 and runs forwards over the lateral margin of the hard palate, about ^ in. from the alveolar margin, 

 as far as to the foramen incisivum, where it anastomoses with the naso-palatine artery. 



(2) Posterior nasal septal artery, a small vessel which enters through the foramen 

 incisivum. 



(3) Ascending palatine artery, from the external maxillary, which anastomoses by a ramus 

 tonsillaris with the descending palatine. 



(4) Branches from the ascending pharyngeal artery, which enter the soft palate. 



(5) Branches from the rami dorsales linguae of the lingual artery, which pass in the glosso- 

 palatine fold to the palatine tonsil and soft palate. 



The nerves are all derived from branches from the spheno -palatine ganglion. 



(1) Nervi palatini. The most important of these is the nervus palatinus anterior, which 

 passes through the foramen palatinum majus, and divides in the roof of the mouth into branches 

 which run in grooves on the hard palate, and extend forwards nearly to the incisor teeth. 



The others are the nn. palatini medius and posterior, which emerge from the foramina palatina 

 minora, and are distributed to the hard and soft palate. 



(2) N. nasopalatinus (Scarpae). This nerve sends branches to the palate through the foramen 

 incisivum, which join with branches from the anterior palatine nerves. 



For the motor nerves to the muscles of the soft palate, see p. 467. 



The lymph-vessels of the palate pass lateral to the tonsil and the isthmus of the fauces to the 

 upper deep cervical lymph-glands. 



Isthmus Faucium. The isthmus of the fauces is the aperture through which 

 the mouth communicates with the oral part of the pharynx (Fig. 878). It is 



bounded at the sides by the glosso- 

 palatine arches, above by the inferior 

 surface of the soft palate, and below 

 by the dorsum of the tongue ; in width 

 it corresponds pretty closely to the 

 cavity of the mouth. 



The arcus glosso - palatini (O.T. 

 anterior pillars of the fauces) are two 

 prominent folds of mucous membrane 

 which bound the isthmus of the fauces 

 on each side (Fig. 878). Each contains 

 a glosso-palatine muscle in its interior. 

 They are continuous above with 

 the inferior surface of the soft palate, 

 a little way (about 8 mm.) anterior 

 to its free edge, and near the base of 

 the uvula, and they pass downwards 

 and slightly anteriorly to join the 

 side of the tongue a little behind its 

 middle. 



The arcus pharyngo- palatini (O. r 



posterior palatine arches) are two verti- 

 FIG. 878. OPEN MOUTH SHOWING PALATE AND F . , , * 



PALATINE TONSILS. ca l folds of mucous membrane whi( 



It also shows the two palatine arches, and the pharyngo- P aSS from the Soft P alate to the si 



nasal isthmus, through which the nasal part of the Wall of the pharynx. Each COntai 



pharynx, above, communicates with the oral portion a muscle, the pharvngO - palatin 



of the pharynx, below. mi _ , i *. -u 



I he pnaryngo-paiatme arches are 

 scribed in connexion with the palatine tonsil (p. 1145). 



Gingivse. The gums are composed of the red firm tissue which covers t 

 alveolar borders of the maxillae and. mandible, and surrounds the necks 

 the teeth. In structure they consist of dense fibrous tissue, inseparably uni 

 to the periosteum, covered by mucous membrane. They are richly suppli 

 with blood-vessels, but sparsely with nerves, and are covered by stratifi 

 squamous epithelium. Around the neck or more correctly the base of the crown 

 of each tooth, the gum forms a free overlapping collar, and at this 

 particularly it is closely studded with small papillae, visible to the naked eye. 



In thickness it usually measures from 1 to 2 mm. 



ongue 



