512 NERVOUS SYSTEM 



the attrahens aurem and the corrugator supercilii muscles, are also 

 paralyzed. The most prominent symptom of paralysis of these muscles 

 is inability to corrugate the brow on one side. 



Paralysis of the muscles that dilate the nostrils has been shown to 

 have an important influence on respiration through the nose. In in- 

 stances of complete paralysis of the nostril of one side, there frequently 

 is some difficulty in inspiration, even in the human subject. 



Physiologists have noted an interference with olfaction, due to the 

 inability to inhale with one nostril, in cases of facial paralysis. The 

 influence of the nerve in the act of conveying odorous emanations to 

 the olfactory membrane is sufficiently evident after what has been said 

 concerning the action of the facial in respiration. 



The effects of paralysis of the other superficial muscles of the face 

 are manifested in the distortion of the features, on account of the unop- 

 posed action of the muscles of the sound side, a phenomenon that is 

 sufficiently familiar. When facial palsy affects one side and is complete, 

 the angle of the mouth is drawn to the opposite side, the eye on the 

 affected side is widely and permanently opened, even during sleep, and 

 the face has on that side a peculiarly expressionless appearance. When 

 a patient affected in this way smiles or attempts to grimace, the dis- 

 tortion is much increased. The lips are paralyzed on one side, which 

 sometimes causes a flow of saliva from the corner of the mouth. In the 

 lower animals that use the lips in prehension, paralysis of these parts 

 interferes considerably with the taking of food. The flaccidity of the 

 paralyzed lips and cheek in the human subject sometimes causes a puff- 

 ing movement with each act of expiration, as if the patient were smoking 

 a pipe. 



The buccinator is not supplied by filaments from the nerve of masti- 

 cation but is animated solely by the facial. Paralysis of this muscle 

 interferes materially with mastication, from a tendency to accumulation 

 of the food between the teeth and the cheek. Patients complain of this 

 difficulty, and they sometimes keep the food between the teeth by press- 

 ure with the hand. In the rare instances in which both facial nerves 

 are paralyzed, there is very great difficulty in mastication, from the 

 cause just mentioned. 



The action of the external branches of the facial is thus sufficiently 

 simple ; and it is only as its deep branches affect the sense of taste, the 

 movements of deglutition, etc., that it is difficult to ascertain their exact 

 office. As this is the nerve of expression of the face, it is in the human 

 subject that the phenomena attending its paralysis are most prominent. 

 When both sides are affected, the aspect is remarkable, the face being 

 absolutely expressionless and looking as if it were covered with a mask. 



