Neuralgia of the Trigeminus. Paralysis of the Facial Nerves. 721 



Acute cerebral meningitis may, in some cases, give rise to tonic 

 or clonic contractions of the muscles supplied by the trigeminus. 



Tonic-clonic spasms have been observed in the area supplied by the trige- 

 Tuinus in a horse showing symptoms of sleepy staggers (Hutyra & Marek). The 

 lower jaw was pressed spasmodically against the upper, the angle of the lip and 

 the upper lip on both sides were drawn upwards, and the lower lip downwards, 

 giving the horse an appearance resembling a dog gnashing its teeth. The muscles 

 of mastication showed more or less persistent contractions. The attacks occurred 

 in a remarkable way during feeding, every time the animal opened its mouth a 

 little widely. There" were no detectable disturliances of sensibility or other abnor- 

 malities to be discovered in the mouth. 



Neuralgia of the Trigeminus (Tic douloureux). Bielefeld, Liau- 

 tard, Strel)el and Williams claim to have observed the disease. Will- 

 iams observed it in horses of very active temperament, and more fre- 

 quently during movement than rest. There was restless tossing of the 

 head and rubbing of the lips against any object at hand. In three 

 cases resection of the infra-orbital nerve caused disappearance of the 

 symptoms, while in one case there was only improvement. Bielefeld ob- 

 served increased sensitiveness and hyperidrosis in the area supplied by 

 the nerves.— (Bielefeld, Pr. Mt., 1856-57, 103.— Liautard, Bull., 1903, 

 40.) 



3. Paralysis of the Facial Nerves. 



Occurrence. Paralysis of the facial nerves occurs with 

 moderate frequency in the horse, but only rarely in the other 

 species. 



Etiology. Anatomical considerations and the general con- 

 ditions of their employment suggest that traumatism is the 

 principal cause of facial paralysis in horses, the point where 

 the nerves turn the posterior border of the jaw being exposed 

 to various injuries. In many cases cold seems to play a part, 

 especially when the animal is hot and stands facing or sideways 

 to a cold wind, or when in winter an animal stands opposite 

 an open mndow or door in the stables. 



In rare cases the paralysis may be caused by inflammatory 

 infiltration of the pharyngeal and parotid regions, the growth 

 of a neoplasm involving the ligaments of the temporo-maxillary 

 articulation (fibrosarcoma, Tempel), a subarticular melanoma, 

 a dental cyst (Deghilage), or an abscess in the long cornu of 

 the hyoid bone (Jewtichilew). Sometimes neuritis is the cause. 

 Dexler found extensive cellular infiltration and degeneration 

 of the nerve fibers in both facial nerves in the neighborhood 

 of geniculate ganglion. The facial paralysis which appears 

 to be common in dourine is due to a neuritis, and the same 

 holds good in the case of paralysis seen in some cases of influ- 

 enza. In many cases paralysis of the facial nerves is due to 

 disease in distant organs (wounds, laminitis, cellulitis, colic), 

 and according to Dieckerhoff the cause in such cases is a septic 

 intoxication. In vie\v of the fact that the nerve is exposed to 

 injury at the point where it turns round the jaw the cause of the 



