368 DISEASES OF THE PERIPHERAL NERVES. 



partly from the fact that muscular contractions only occur on the sound 

 side, while the other remains motionless, and partly because the con- 

 tracting muscles upon the sound half of the face are not counterbal- 

 anced by the palsied half, so that the countenance is drawn to one side. 

 Even during rest the face remains more or less distorted and unsym- 

 metrical. The palsied angle of the mouth is lower than the healthy 

 one, the nostril is narrower, and all the pits and depressions are ef- 

 faced. The point of the nose and the mouth are drawn over toward 

 the sound half of the face. All this deformity is due to the want of 

 balance between the healthy muscles of one half the face and their 

 palsied antagonists. In the same way there is lagophthalmos of the 

 affected side, from a preponderance of the unpalsied levator palpebnw 

 superioris over its palsied antagonist, the orbicularis palpebrarum. 

 When paralysis of the facial is bilateral, the face becomes void of all 

 expression, and the patient laughs and weeps without exhibiting any 

 play of countenance. I have never seen such a case myself, but can 

 easily believe that the aspect of a person whose face remains motion- 

 less, even while he is laughing loudly, will present the hideous appear- 

 ance of a mask. The impairment of the sense of taste, the distortion 

 of the uvula, and deviation of the 'tongue, though less obvious symp-. 

 toms, are equally constant. It is uncertain whether the obtuseness of 

 the sense of taste depends upon diminution of the secretion of saliva, 

 and consequent dryness of the mouth, or whether the chorda tympani 

 nerve, by erecting the papilla of the tongue, aids the gustatory sense. 

 Displacement of the uvula to the sound side is accounted for by the 

 fact that the motor nerve-fibres, passing through the nervus petrosus 

 superficialis major to the sphenopalatine ganglion, from which the de- 

 scending palatine branches proceed, only contract the muscles of the 

 uvula upon the side which is not palsied. This explanation, however, 

 is not absolutely satisfactory. 2 



Regarding the deviation of the tongue, we refer to what we have 

 already said while treating of apoplexy, as this symptom is of more 

 common occurrence in cerebral than in peripheral paralysis. In a pre- 

 vious chapter we have given a detailed explanation of why the reflex 

 motion should be impossible in complete peripheral palsy of the facial, 

 and why the electric contractility of the muscles of the face soon be- 

 comes extinct. In recent and uncomplicated cases, the sensibility of 

 the paralyzed half of the face is normal. When of longer standing, 

 it generally becomes somewhat blunted, probably in consequence of 

 nutritive disorder of the region supplied by the affected nerve. This 

 shows itself chiefly through emaciation and flabbiness of the palsied 

 part of the face, by the disappearance of the fat, and by the shrivelled 

 condition of the skin. 



