374 DISEASES OF THE SKULL. 



McFadyean failed to effect a cure even after several times operating. 

 On post-mortem examination of the case he found the opening of 

 the Eustachian tube contracted and indurated. In one case Degive 

 succeeded in effecting recovery by making a large opening into the 

 pouch and injecting it daily with a solution of silver nitrate (1 to 200). 

 Thomassen recommends opening the sac at the posterior border of 

 the under jaw, dilating the opening with the forefinger, and washing 

 out with some antiseptic fluid. On account of the dyspnoea often 

 present, the same principles obtain as in treatment of catarrhal 

 affections of the guttural pouch. 



VII.— DISEASES OF THE SKULL. 

 (1.) FRACTURES AND INJURIES TO THE CRANIAL BONES. 



The cranial cavity is formed by the parietal, interparietal, 

 temporal, occipital, and sphenoid bones, in front by the ethmoid 

 and the upper section of the frontal. Fractures of the cranial bones 

 are caused by falls (either forwards or backwards), collisions, kicks, 

 horn thrusts, and in carnivora by bites from other animals, kicks, 

 and similar injuries. The sphenoid is sometimes broken by the 

 contrecowp resulting from collisions. Subcutaneous fractures of the 

 above-named bones occur, but complicated fractures are most 

 common. In some cases concussion exists simultaneously with 

 injury of the brain or spinal cord produced by dislocated fragments 

 of bone. 



Konig has given a resume of the frequency with which the cranial 

 bones are respectively fractured, based on the official statistics of 

 the Prussian army. Of 2,984 cases of cranial fracture, 55 affected 

 the occipital bone, 40 the sphenoid, 33 the frontal, 10 the parietal, 

 4 the temporal, and 2 the ethmoid. 



The symptoms of cranial fracture are, in the absence of displace- 

 ment, often very ill-defined. Local swelling and pain are often 

 absent, even slight depressions in the skull often escape observation, 

 and do not always produce cerebral disturbance. Should the dis- 

 location be considerable, marked interference with consciousness, 

 equilibrium, respiration, and circulation may result. The animal 

 shows spasmodic seizures, and is unable to stand. 



Prognosis is uncertain. Where the fracture is complete and 

 displacement has occurred the condition is exceedingly grave. 

 Recovery may occur, however, even in such cases. Uebelen saw a 

 dog and Meyer a cow recover, in both of which the brain was exposed 



