.*K)4 fistula of the ear. 



Such teeth may be present (abnormally) in other positions, as 

 the gums, the superior maxillary sinus, the testicle, and the ovary. 

 In the malar bone they often remain unnoticed, until either 

 acute inflammation produces swelling and prominence, or until 

 attention is accidentally directed to the fistulous opening. They 

 are commonest in young animals, especially during the period of 

 dentition, and may even be seen within a few weeks after birth. 

 The swelling is hard and firmly connected with the malar bone, over 

 which the skin is freely movable. Sometimes cellulitis develops, 

 followed by abscess formation, but producing no great disturbance. 

 In horses of little value objection is accordingly raised to removal 

 of the adventitious teeth. 



Fig. 331. — Pre-auricular fistula due to presence of a clentigerous cyst. 



Treatment. Where treatment is necessary the swelling is opened 

 to the bottom, the tooth removed, the interior disinfected, and 

 recovery usually occurs in two to four weeks. Ligature of vessels 

 is rarely necessary. When the tooth is deeply implanted in one of 

 the cranial bones it may be removed with forceps, but in such 

 case there is considerable danger of meningitis, even though 

 strict antisepsis be observed, and it may be advisable to renounce 

 operation. The disease occurs very seldom in animals other than 

 the horse. Verwey found a dental cyst on the petrous temporal 

 bone of a dog, which suffered in consequence from otitis externa. 



Dermoid cysts closely resemble those above described, and occur 

 in similar situations, but usually contain a mass of deeply pigmented 

 tissue more or less covered with hair. 



