54 



APPLIED ANATOMY. 



are affected, the pus may go between the pterygoid muscles, or around the internal 

 carotid artery and project and open into the pharynx. It may also break into the 

 carotid artery or jugular vein, or perforate through the fascia below and go down 

 the neck. Large abscesses and sloughs may be followed by a parotid fistula. 



Lines of Incision for Abscess. The manner of opening a parotid abscess 

 depends on its location and size. If it is desired to open an abscess anterior to a 

 point 1.5 cm. or about half an inch in front of the ear, the structures to be avoided 

 are the duct and facial nerve. The incisions are to be made parallel to the zygoma, 

 and the duct is to be avoided by not cutting on a line joining the lower edge of the 

 cartilage of the ear with the middle of the upper lip. The branches of the facial 



nerve lie deep and are to be avoided by 

 making the incision parallel to their course 

 and not extending it too deeply. After in- 

 cising the skin, the deeper tissues may be 

 separated by introducing a pointed pair of 

 haemostatic forceps and opening the blades. 

 In operating in the region below the ear, 

 the blood-vessels are to be avoided. To do 

 this incise the skin longitudinally, not trans- 

 versely, and open the deep parts carefully 

 with the haemostatic forceps, as already 

 described. Another method, when the ab- 

 scess is farther forward, is to make a hori- 

 zontal incision rather low down on the angle 

 of the jaw and then introduce a grooved 

 director or haemostatic forceps from below 

 upward. 



Tumors of the parotid gland are liable 

 to be mixed in character, with a sarcoma- 

 tous element. They are often fairly cir- 

 cumscribed and, particularly if they do 

 not involve the parotid duct, can be re- 

 moved comparatively readily. If they are 

 malignant and large, complete removal is 

 practically impossible. The possibility of 

 parotid fistula and paralysis of the facial 

 nerve following operation on this gland should always be borne in mind and explained 

 to patients. The presence of facial paralysis is indicative of malignancy (see Fig. 63). 

 The parotid lymph nodes on or beneath the capsule may become enlarged and 

 inflamed and resemble true parotiditis. There is one node just below the zygoma 

 and in front of the ear that is not infrequently enlarged in strumous children. This 

 is apt to be involved when affections of the lids or scalp are present. In open- 

 ing abscesses of these nodes there is little likelihood of injuring either the nerve or 

 the duct, because the nodes are superficial. The transverse facial artery is usually 

 too small to cause trouble. The possibility of its supplying the coronary arteries 

 of the lips, as already described, in which case it would be very large, should be 

 remembered. 



THE UPPER JAW. 



The upper jaw carries the upper teeth and contains the maxillary sinus or 

 antrum of Highmore. The affections of the antrum will be alluded to in the chapter 

 on the nose (see page 103). Fractures of the superior maxilla involve the nasal 

 process, the alveolar process, or pass transversely through the body of the bone. 

 The nasal process is sometimes broken in fractures of the nose. In this injury, the 

 lachrymal canal and sac may be injured and the flow of tears through them pre- 

 vented, causing the tears to run over the cheek. 



Fractures of the alveolar process are common enough as a result of blows and 

 extracting teeth. These fractures, as they communicate with the mouth through the 

 broken gums or mucous membrane or tooth socket, are necessarily compound, and 



FIG. 63. Malignant tumor of the parotid gland pro- 

 ducing facial paralysis (author's case). 



