344 FRACTURE <)F THE LOWER JAW. 



of the border of the alveoli of the lower incisors are often seen, in 

 consequence of the animal biting, being kicked, or falling and striking 

 fixed objects. Fractures of the joint or coronoid process, although 

 occasionally reported, occur less frequently. 



Subcutaneous fractures of one branch of the lower jaw are not 

 so readily diagnosed; suddenly developed difficulty in mastication 

 is the chief symptom. In fractures in the region of the molars the 

 teeth may continue to hold the fragments together in such a way 

 that neither crepitation nor unusual mobility of the parts can be 

 detected. In such cases one or more teeth may be found to be loose. 



Symptoms. In transverse fractures of the body of the bone 

 the chin and lower incisors hang limply and are abnormally mobile, 



Fig. 326. — Incomplete union of fracture of the body of the lower jaw. 

 From a photograph. 



while crepitation may be detected. Fractures of the coronoid process 

 or joint, or in their neighbourhood, often interfere seriously with 

 mastication, and may be mistaken for inflammation of the articu- 

 lation. The broken fragments of the coronoid process are drawn 

 upwards by the temporalis muscle, and can be detected on palpation. 

 Prognosis. Fractures in the median line and subcutaneous 

 injuries of one branch unite regularly and completely in from three 

 to five weeks. Double-sided fractures present the greatest difficulty, 

 and often affect mastication so seriously that condition is lost in a 

 marked degree. Transverse fractures of the body are difficult to 

 set, and sometimes eventuate in formation of callus fibrosus, with 

 sinking of the alveolar margin and protrusion of the tongue (Fig. 326). 

 Griin cured the above transverse fracture in a calf by applying a 



