214 ANIMAL DENTISTRY. 



coronoid process prevents luxation. In the dog it occurs 

 while masticating bones, or in yawning. 



Pathological Anatomy — The dislocation is a forward 

 one in all instances and like all luxations is accompanied with 

 considerable injury to the binding and secretory ligaments. 

 It is usually bilateral, but may be unilateral. 



Symptoms — Inability to close the mouth is the pathogno- 

 monic symptom. The jaw will be locked open and cannot 

 be closed by force. In the unilateral luxation the jaw is open 

 but is turned to one side. 



Treatment — A piece of hard wood two feet long and 

 about one-half inch thick, wide enough to rest along both 

 inferior arcades, is firmly fastened to the lower jaw (within 

 the mouth) by wrapping with strong cord. The stick thus 

 adjusted is then used as a lever to depress the jaw pos- 

 teriorly. When sufficient pressure is brought to bear the 

 condyle snaps into its cavity. 



BIT GNATHITIS. 



Synonyms — Bit contusions. Fractured jaw. Bit sores. 



Definition — A traumatic inflammation of the interdental 

 space of the lower jaw produced by bruising with the bit. 



Etiology — Bit gnathitis is caused by the use of harsh bits, 

 especially curb bits. The straight or snaffie bit will occasion- 

 ally produce the trouble in horses inclined to "pull" heavily 

 upon reins in the hands of a powerful reinsman. Habitual 

 "pullers" are the susceptible subjects, when attempts are 

 made to control them by the use of harsh riggings. The 

 condition is seen most frequently in the coach horse, saddle 

 horse, hunter and polo ponies, and in the light harness horse 

 that is difficult to control. 



Pathological Anatomy — The lesion consists of an intense 

 local stomatitis, periostitis and osteitis occurring simultane- 

 ously. The inflammatory action may be confined to a small 



