FKACTUKES OF THE CRANIAL BONES. 107 



fracture must be exposed by a crucial incision, and the bone 

 raised by an elevator. Sometimes it is possible to introduce the 

 elevator under the edge of the fractured bone without using the 

 trephine; in the majority of cases, however, it will be found 

 necessary to remove a part of the bone that is not depressed, so 

 as to admit of the introduction of an elevator, by which the 

 depressed part may be raised to a level with the surrounding 

 parts of the skull. 



The best form of trephine is the one with a moveable centre- 

 bit. The elevator or lever is a very simple instrument, and can 

 be made by the nearest blacksmith, being merely a chisel with a 

 slight curve or elbow. Should the fracture of the inner table be 

 comminuted, all loose portions must be carefully picked out 

 with the forceps. 



Whilst recommending the above treatment, I am bound to 

 admit that the force sufficient to cause fracture of the bones of 

 the skulls of our patients is generally sufficient of itself to pro- 

 duce instant and fatal concussion of the brain ; but, on the other 

 hand, it will be found, during a long period of practice, that 

 cases as described occur, especially in a city like Edinburgh, 

 where the streets are hilly, paved with granite, and the horses 

 shod with calkins and toe-pieces, which seem to take from the 

 poor animals the power of falling naturally when they make a 

 slip, and to cause them to tumble head foremost. From these 

 causes, fractures of all kinds are of frequent occurrence. 



3. Punctured Fracture. — This is caused by a sharp body, as a 

 pitchfork, or by the animal falling on a pointed instrument of 

 any kind ; a mere puncture or cavity being the outward visible 

 effect, but the internal table, from its brittleness, is injured to a 

 greater extent than the outer. This fracture is sometimes called 

 "star-like" or radiated fracture, from the fact that there are 

 numerous fissures or cracks in the bone, radiating from the 

 centre of the fracture. 



This is a very dangerous form of fracture, requiring immediate 

 trephining, although symptoms of compression may be absent. 

 The danger arises from the fact that spiculse of the inner table 

 are always driven inwards, and if these be not removed, it is cer- 

 tain that inflammation will ensue. If the operation be delayed 

 till then, the animal will most assuredly die. 



After the depressed fragments have been removed (and it may 



