THE SALIVARY GLANDS 



59 



without inwards, to open into the cavity of the mouth opposite 

 the third upper molar tooth. 



In structure the duct is made up of an internal mucous lining 

 and an outer layer of connective tissue, with elastic fibres arranged 

 both circularly and longitudinally. 



If it should be necessary to functionally destroy the parotid gland 

 this may be done by applying a ligature to the duct. The best 

 seat to pick up the duct is just where it is curving round the lower 

 jaw. Plate XXXII. shows this seat dissected, and on reference to it the 

 position of the duct with regard to the accompanying vein and 

 artery will be evident. 



After making a cutaneous incision in the position indicated careful 

 dissection is necessary to free the duct from the surrounding structures, 

 to which it is somewhat firmly adherent. 



It is not uncommon to find salivary calculi in the duct, due to 

 precipitation of the salts of the saliva. These calculi are best left alone 

 unless there is a suspicion that the lumen of the duct is completely 

 obstructed, and if such be the case it becomes necessary to abstract 

 the calculus. 



The seat is usually quite close to the lower jaw. There is no 

 difficulty in cutting down on to, and removing the calculus. The 

 difficulty lies in eifectively closing the wound, and preventing the 

 formation of a salivary fistula as a complication. 



It will be noted that the structures cut through in making an 

 incision into the duct are skin and skin muscle, fascia, and the wall of 

 the duct. These should be sutured in separate layers in closing the 

 wound, several fine sutures being inserted in the wall of the duct. 

 Adhesive strapping should then be applied to support the sutures, 

 and the food given should be moist. Dry food is to be strictly 

 avoided, owing to the amount of salivation which their mastication 

 excites, and the jaws should be kept as still as possible. 



If a salivary fistula should form as a complication consequent on the 



