472 



THE NERVOUS SYSTEM. 



become smooth and expressionless. The same is true of the cheek, 

 which, as well as the nostril, is flattened and collapsed. The corner 

 of the mouth hangs downward, and owing to imperfect closure of 

 the lips there is sometimes a continual escape of saliva from this point. 

 Beside these symptoms there is also a deviation of the mouth toward 

 the sound side, owing to the facial muscles on that side being no longer 

 antagonized by the opposite. In many instances this deviation is not 

 observable during a state of quiescence, both sets of muscles being 

 habitually relaxed ; and it becomes evident only when the patient 

 uses those of the sound side, as in speaking, whistling, or laughing, 

 or when the emotions are excited. But in cases where the face has 

 naturally an abundance of expression, the distortion of the features, 



FIG. 125. 



FACIAL PARALYSIS of the right side. 



and their different appearance on the two sides, are distinct at all 

 times, becoming still more marked when the patient is excited or 

 engaged in conversation. 



Another effect of facial paralysis in man is difficulty in drinking and 

 in mastication. The difficulty in drinking is due to deficient action of 

 the orbicularis oris on the affected side ; so that the lips at this corner 

 of the mouth cannot be kept in contact with the sides of the goblet. 



