PARALYSIS OF THE FACE. 



567 



owing to impairment of tlie respiratory organs in the throat or 

 chest, are signs of the injury to the nerve being more deeply 

 placed than its point of passage below the joint of the jaw. These 

 nerves communicate with nerves (the tenth pair) which largely 

 influence the action of breathing and of the heart. Difficulty of 

 breathirtg may be also cau,sed, especially during work, by falling in 

 of the nostrils, owing to the muscles which dilate their opening, 

 being paralysed. If the muscles only of the lips, nostrils and cheek 

 be implicated, it may be concluded that the seat of injury is on 



Fig. 151. — Paralysis of lips on bolh sides. 



the superficial course of the nerve. As they are motor nerves 

 (their action being to stimulate muscular contraction) ; arrest of 

 their function through injury, will be followed by a continued 

 flaccid condition of the muscles which they supply. The paralysis 

 may be on one side or on both. When the nei"\'e on one side only 

 is affected, the lip will be drawn away from that .side, owing to 

 the paralysed muscles not being able to oppose the action of those 

 of the healthy side. If both nerves be implicated (Fig. 151), the 

 lips will hang loose and motionless ; and saliva will continuallv 

 trickle from the lower one. As the sufi'erer has lost the power of 

 prehension with his lips, he will seize his food with his teeth, and 



