SPLANCHNOLOGY. 185 
isthmus faucium, is bounded above by the velum and uvula, below by the 
tongue, on each side by the arches of the palate. 
The anterior part of the palate, or hard palate, is formed of the palate 
plates of the maxillary and palate bones, covered by mucous membrane 
and glands; the posterior part of the palate, or soft palate, or velum pendu- 
lum, consists of a dense aponeurosis, and of several muscles and glands, 
inclosed in mucous membrane. 
The cheeks are formed of mucous membrane, covered by the buccinator 
and a quantity of fat; several small mucous glands lie between the mem- 
brane and this yasile: and towards the upper and back part on each side 
we perceive the small opening of Steno’s duct. 
The lips are composed of integuments with more or less of fat, muscles, 
vessels, nerves, glands, and mucous membrane. The skin is delicate and 
vascular, particularly at the red borders, where it is continuous with the 
mucous membrane of the mouth. The cuticle is continued over the latter 
to line the whole cavity as a very fine epithelium. The muscles are, the 
orbicularis oris, with which the fibres of many others (already described) 
intermingle. ‘The arteries of the lips are the coronary vessels, assisted by 
their inosculations with branches of the internal maxillary artery. The 
sentient nerves are derived from the infra-orbital and dental branches of 
the fifth, and the motor from the seventh pair. The labial glands are very 
numerous; they are rounded and pale, and are situated in the submucous, 
loose cellular tissue, at some distance from the red border. The mucous 
membrane is continued from each lip to the alveolar processes of the 
maxille, and forms in the centre of each a small fold or franum; this is 
larger in the upper than in the lower lip. 
The mouth is lined throughout by mucous membrane, which is continu- 
ous with the cutis on the lips, and extends posteriorly through the pharynx, 
whence it ascends to line the nares, the Eustachian tube, and tympanum, 
on each side, and descends to line the cesophagus and larynx; it is also 
continued into the ducts of the sublingual, submaxillary, and parotid glands ; 
as it is reflected from one surface to another, it forms folds or frzena, as 
between the lips and alveoli and beneath the tongue; at the sides of the 
fauces, also, it forms two semilunar folds on each side, called the pillars or 
Sate of the palate; these folds inclose muscular filsees which we shall 
examine afterwards. 
On looking into the mouth, either in the living or dead subject, the 
following objects strike the attention: inferiorly, the tongue and inferior 
teeth ; laterally, the cheeks; posteriorly, the back part of the pharynx; 
superiorly, the superior teeth, the hard and soft palate, from the centre of 
the latter the uvula, and from the sides, the pillars or arches descending to 
the tongue and pharynx; in the recess between these pillars on each side, 
the tonsils or amygdala are also seen ; lastly, if the tongue be drawn forward, 
the epiglottis comes into view. 
Pl. 129, fig. 80, cavity of the mouth: ', palate; *, velum palati; °, uvula; 
*, arch of the palate to the mucous membrane of the pharynx; °, arch to the 
tongue; °, tonsil; ’, tongue; *, epiglottis, and beneath this the pharynx 
891 
