chap, viii.] THE MOUTH. 103 



met with over the site of the sublingual gland, and 

 is due to the dilatation of one of the gland ducts 

 that has become obstructed, or to an occluded mucous 

 follicle. The mucous membrane of the floor of the 

 mouth, as it passes forwards to be reflected on the 

 gums, is attached near to the upper border of the 

 jaw. The genio-hyo-glossus is attached near the 

 lower border. Between these two parts (the mucous 

 membrane and the muscle) there is, according to 

 Tillaux, a small space lined with squamous epithelium. 

 To this cavity the name is given of the sublingual 

 bursa muccsa. It is constricted in its centre by the 

 frsenum linguae, and is said to be the seat of mischief 

 in " acute ranula." 



When the mouth is widely opened the pterygo- 

 maxillary ligament can be readily seen and felt 

 beneath the mucous membrane. It appears as a 

 prominent fold running obliquely downwards behind 

 the last molar teeth. A little below and in front of 

 the attachment of this ligament to the lower jaw, the 

 gustatory nerve can be felt as it lies close to the bone 

 just below the last molar. This nerve is sometimes 

 divided for the relief of pain in cases of carcinoma 

 of the tongue. Mr. Moore's method of dividing it is 

 as follows : " He cuts the nerve about half an inch 

 from the last molar tooth, at a point where it crosses 

 an imaginary line drawn from that tooth to the angle 

 of the jaw. He enters the point of the knife nearly 

 three-quarters of an inch behind and below the tooth, 

 presses it down to the bone, and cuts towards the 

 tooth " (Stimson). This nerve, as it lies against 

 the bone, has been crushed by the slipping of the 

 forceps in the clumsy extraction of the lower molar 

 teeth. 



The coronoid process of the lower jaw can be 

 easily felt through the mouth, and is especially distinct 

 when that bone is dislocated. It may be noted that 



