502 MOUTH HARD PALATE. 



C Caecum, 



Large intestine < Colon, 

 ( Rectum. 



The Mouth is the irregular cavity which contains the organs of taste and 

 the principal instruments of mastication. It is bounded in front by the 

 lips ; on either side by the internal surface of the cheeks ; above by the 

 hard palate and teeth of the upper jaw; below by the tongue, by the mu- 

 cous membrane stretched between the arch of the lower jaw and the under 

 surface of the tongue, and by the teeth of the inferior maxilla ; and behind 

 by the soft palate and fauces. 



The Lips are two fleshy folds formed externally by common integument, 

 and internally by mucous membrane, and containing between these two 

 layers the muscles of the lips, a quantity of fat, and numerous small labial 

 glands. They are attached to the surface of the upper and lower jaw, and 

 each lip is connected to the gum in the middle line by a fold of mucous 

 membrane, the fraenum labii superioris and fraenum labii inferioris, the 

 former being the larger. 



The Cheeks (buccae) are continuous on either hand with the lips, and 

 form the sides of the face ; they are composed of integument, a large 

 quantity of fat, muscles, mucous membrane, and buccal glands. 



The mucous membrane lining the cheeks is reflected above and below 

 upon the sides of the jaws, and is attached posteriorly to the anterior 

 margin of the ramus of the lower jaw. At about its middle, opposite the 

 second molar tooth of the upper jaw, is a papilla, upon which may be 

 observed a small opening, the aperture of the duct of the parotid gland. 



The Hard palate is a dense structure, composed of mucous membrane, 

 palatal glands, fibrous tissue, vessels, and nerves, and firmly connected to 

 the palate processes of the superior maxillary and palate bones. It is 

 bounded in front and on each side by the alveolar processes and gums, 

 and is continuous behind with the soft palate. Along the middle line it 

 is marked by an elevated raphe, and presents upon each side of the raphe 

 a number of transverse ridges and grooves. Near its anterior extremity, 

 and immediately behind the middle incisor teeth, is a papilla which cor- 

 responds with the termination of the naso-palatine canal, and has been 

 supposed to be endowed with a peculiar sensibility. 



The Gums are composed of a thick and dense mucous membrane, 

 which is closely adherent to the periosteum of the alveolar processes, and 

 embraces the necks of the teeth. They are remarkable for their hardness 

 and insensibility; and for their close contact, without adhesion, to the 

 surface of the tooth. From the neck of the tooth they are reflected into 

 the alveolus, and become continuous with the periosteal (peridental) mem- 

 brane of that cavity. 



The Tongue has been already described as an organ of sense ; it is in- 

 vested by mucous membrane, which is reflected from its under part upon 

 the inner surface of the lower jaw, and constitutes with the muscles be- 

 neath, the floor of the mouth. Upon the under surface of the tongue, 

 near its anterior part, the mucous membrane forms a considerable fold, 

 which is called the freenum linguce ; and on each side of the frasnum is a 

 large papilla, the commencement of the duct of the submaxillary gland, 

 and several smaller openings, the apertures of the ducts of the sublingua] 

 gland. 



