Symptoms. 719 



branch) be alone affected the skin over the forehead up to the 

 level of the ears (tig. 102), the eyelids, the nasal mucous mem- 

 brane, the surface of the eyeball and the cornea are insensitive. 

 Pressure on the cornea does not cause closure of the lids nor 

 retraction of the eye. Particles of dust and dirt settling on the 

 surface of the eye are not perceived and consequently not re- 

 moved. As a result of this the cornea becomes cloudy and soon 

 ulcerates, thus allowing the inflannnation to spread to deeper 

 parts of the eye (ophthalmia neuroparalytica). 



If the second branch be paralyzed (the superior and in- 

 ferior maxillary branches) there is loss of sensation of the skin 

 of the face, of the dorsum of the nose, the cheeks and lips and 

 the mucous membrane of the tongue on the diseased side (fig. 

 102). The tongue is injured during mastication without the 

 animal feeling it. The upper lip on the diseased side is drawn 

 towards the opposite side owing to loss of muscular tone, while 

 the insensitive half of the lower lip moves slowly. Simultane- 

 ous paralysis of the vaso-motor nerves maj^ cause intense red- 

 dening of the mucous mem- 

 branes. In cases of paralysis 

 caused by compression the an- 

 esthesia is always preceded by 

 hyperesthesia. 



Disease of the lower branch 

 causes also paralysis of the mus- 

 cles of mastication (masseter, 

 temporal, internal and external 

 pterygoids). The animal mas- 

 ticates with the sound side only, 

 the teeth of the opposite side 



scarcely coming into contact Fig. 102. Paralysis of the trigemin- 



with each other. One can easily f ^ "«^^^, ^^^ *« contusion of the 



-,„„,,., ,, • brain. The dark line indicates the 



convince Oneselt Ot this by allow- upper and posterior line of the anes- 



ing the animal to chew some thetic area, 

 hard object. The lower row of 



incisors is pulled away from the paralyzed side and a narrow 

 space is left between the upper and lower rows. The teeth on 

 the paralyzed side do not wear properly and particles of food 

 collect between the cheek and the teeth owing to the insensitive- 

 ness of the mucous membrane. If the hand be placed on the 

 temporal region or on the masseters during mastication it can 

 be noticed clearly that while the muscles on the sound side con- 

 tract, those on the opposite side remain quiescent. In time 

 the paralyzed muscles undergo atrophy. 



In dogs paralysis of the trigeminal nerve resulting from 

 crushing by the contraction of the muscles of mastication tends 

 to be bilateral and involves the motor branch only. The mouth 

 is held open and the lower jaw is dropped, but it is easily raised. 

 The tongue is dry and hangs out of the mouth, there is a flow of 

 saliva (fig. 102), food and water cannot be taken, but food 



