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On the Nerves of the Face ; being a second Paper on that Subject. 

 By Charles Bell, Esq. F.R.S. Read May 28, 1829. [PA7. 

 Trans. 1829, p. 317.] 



After recapitulating the contents of his former paper, the author 

 cites cases which have occurred since its publication, in support of 

 his doctrine, first, that the sensibility of the head and face depends 

 on the fifth pair of nerves ; secondly, that the muscular branches of 

 that pair are subservient to mastication ; and, thirdly, that the portio 

 dura of the seventh pair controls those motions of the parts of the 

 face, whether voluntary or involuntary, which are connected with 

 respiration. Instances are given of lesions of the portio dura, from ac- 

 cident or from disease, followed by paralysis of the muscles on the 

 same side of the face, while the sensibility remained. On the other 

 hand, cases are related of injury to the fifth pair, being attended with 

 loss of sensibility in all the parts receiving branches from the injured 

 nerve, while the power of motion continued unimpaired. In one 

 case of this description, where one half of the under lip had become 

 insensible, on a tumbler being applied to the mouth, the patient 

 imagined it was a broken glass that he touched. A similar delusion 

 was experienced by another patient, in whom the half of the upper 

 lip had been deprived of sensation by an injury to the sub-orbital 

 branch on the same side. From these facts the author deduces the 

 absurdity of the practice of cutting the portio dura for the relief of 

 tic douleureux. 



He next enters into an anatomical description of the course of that 

 division of the fifth pair of nerves, which is unconnected with the 

 Gasserian ganglion, and passes under it, and which he considers as 

 the motor or manducatory portion of the fifth, being distributed to 

 the temporal, masseter, pterygoid, and buccinator muscles ; some 

 branches of it supplying the muscles of the lips, and also the mylo- 

 hyoideus and anterior belly of the digastricus, the action of which is 

 to depress the jaw. 



In proof that this nerve is destined to manducation, the root of the 

 fifth pair being exposed in an ass, and irritated, the jaws closed with a 

 snap ; and on its being divided, the jaw fell relaxed and powerless. 



The author next endeavours to show the necessity of an accord- 

 ance between the motions of the lower jaw and those of the cheeks 

 during mastication ; and the probability that this connexion of mo- 

 tions is brought about by means of the connexions which exist among 

 their respective nerves, and between which a sympathy may in con- 

 sequence be established. In one case violent spasms took place in 

 the masseter and temporal muscles, while the motions of the features 

 were free and unconstrained ; and in another, the muscles of the jaw 

 on one side were paralysed, with loss of sensibility on that side of 

 the face. On the other hand, when the portio dura was paralysed, 

 all the muscles of the face wasted, except those supplied by the fifth 

 pair. 



The author concludes by a warm tribute of acknowledgement to 



