PoO 



PHARYNX. 



in the upper lip a projection in the centre, from 

 which a curved line, gently arching upwards, 

 proceeds laterally, while, in the lower, the 

 centre exhibits a depression, and the line from 

 it proceeds in a contrary direction, so that 

 when the mouth is closed these borders are 

 applied evenly to each other : they are of a 

 red colour, turned outwardly, and marked 

 from before backwards l.y slight wrinkles pro- 

 duced by the contraction of the orbicular 

 muscle ; their chief interest to the anatomist 

 is in showing the continuity of the skin with 

 the mucous membrane. Besides the tegu- 

 mentary coverings of skin and mucous mem- 

 brane, these organs contain within their thick- 

 ness the orbicularis muscle, with which are 

 blended the insertions of the greater number 

 of the muscles of the face (see FACE), whose 

 varied actions render these features so pecu- 

 liarly expressive of the passions: numerous 

 glands, vessels, and nerves, and an areolar 

 tissue complete their structure. The labial 

 glands constitute a thick lamina between the 

 muscular and mucous layers, producing slight 

 elevations upon the surface of the latter ; they 

 resemble the salivary glands in appearance, 

 are of small but varying size, placed close to 

 each other but perfectly distinct, each posses- 

 sing a separate excretory duct, which opens 

 upon the free surface of the mucous mem- 

 brane. The lips are most abundantly supplied 

 with vessels and nerves ; the coronary arteries, 

 from the facial, course along their free borders 

 directly beneath the mucous membrane ; they 

 also receive numerous twigs from the buccal, 

 infra-orbital, and mental branches of the in- 

 ternal maxillary and submental branch of the 

 facial ; the veins accompany the arterial branches; 

 the lymphatics terminate in the glands at the 

 base of the jaw, as evidenced by the frequent 

 enlargement of the latter from the irritation of 

 cancerous or other sores about the lips : the 

 nerves are derived from the portio dura and 

 fifth pair. 



Use. The lips are of great importance, more 

 particularly the lower, in retaining the saliva 

 within the cavity of the mouth, and are actively 

 engaged in the acts of sucking and blowing ; 

 the utterance of many articulate sounds de- 

 pends chiefly upon their action, and when 

 viewed as organs of expression they are parti- 

 cularly adapted by their extreme mobility to 

 indicate the passing thought. 



The cheeks (buccse) form the lateral exten- 

 sible walls of the buccal cavity ; examined 

 from the interior of the mouth they will be 

 found limited above and below by the reflexion 

 of their investing mucous membrane upon the 

 external surfaces of the superior and inferior 

 maxillary bones : their superficial surface is 

 bounded behind by the external ear and the 

 posterior border of the lower jaw, below by 

 the horizontal ramus of the same bone ; supe- 

 riorly they may be arbitrarily separated from 

 the temple by the zygoma, and from the orbit 

 by the lower margin of its cavity, and are con- 

 tinued anteriorly into the sides of the nose and 

 lips ; they therefore present somewhat of a 

 quadrilateral outline, and in the young and 



healthy form a rounded projection outwards, 

 but in the emaciated fall in towards the 

 mouth. The skin of the cheek is smooth, thin, 

 and delicate in front and above, and remark- 

 able for its extreme vascularity, as seen in the 

 act of blushing ; it is covered behind and 

 below in the adult male with hair, and in the 

 aged its surface is more or less furrowed with 

 wrinkles: the subcutaneous cellular tissue is 

 dense and loaded with a variable quantity of 

 fat, a particularly abundant mass of which is 

 lodged between, the buccinator and masseter 

 muscles. The muscular structure of the cheeks 

 has been already described in the article FACE. 

 Between the muscles and mucous membrane 

 are irregularly dispersed a considerable num- 

 ber of buccal glands; they are of small size, 

 similar to those of the lips, and like them open 

 upon the mucous surface by separate ducts : 

 these openings are not likely to be mistaken 

 for that of the parotid duct, which is marked 

 by a very distinct prominence, is of larger size 

 and situated opposite the interval between the 

 second and third molar teeth in the upper jaw ; 

 there is an aggregation of several of these 

 buccal glands, imbedded in the fat between 

 the buccinator and masseter muscles, form- 

 ing a larger glandular mass which opens into 

 the mouth opposite the last molar tooth, and 

 has been called the molar gland. The cheeks 

 receive a rich supply of vessels from the facial, 

 transverse facial, and internal maxillary arteries; 

 the veins correspond to these branches and 

 empty themselves into the internal and external 

 jugular veins. The lymphatics probably ter- 

 minate in the glands of the neck. As with 

 other parts of the face, the cheeks derive their 

 nervous filaments from the portio dura and 

 fifth pair. 



Use. While the tongue guides the food 

 outwardly to the teeth, the cheeks act in re- 

 taining it between them during mastication ; 

 they are employed during the act of sucking, 

 and when distended by air or fluids they are 

 actively engaged in forcibly expelling them, as 

 exemplified in playing upon wind instruments 

 or in squirting liquids from the mouth. 



The palatine arch and gums. The palatine 

 arch or hard palate forms the greater part of 

 the superior boundary of the buccal cavity : 

 it has a parabolic figure, bounded laterally and 

 in front by the teeth, and is continued poste- 

 riorly into the velum palati without exhibiting 

 any line of demarcation : it presents mesial ly 

 a whitish ridge, more prominent before than 

 behind, which commences from a small emi- 

 nence situated immediately behind the incisor 

 teeth and corresponding with the lower orifice 

 of the anterior palatine canal; the ridge then 

 extends backwards and is traceable as far as 

 the uvula ; from it are passing laterally a vari- 

 able number of transverse rugae, apparent only 

 at the anterior part of the palate, its buccal 

 surface being, in the greater part of its extent, 

 perfectly smooth. The palatine arch is framed 

 by the palate processes of the superior maxil- 

 lary and palate bones,* and invested on their 



* See FACt. 



