MR. BELL ON THE NERVES OF THE FACE. 323 



compound, and go off diverging to their destinations. First, there are sent off 

 nerves to the temporal, masseter, and pterygoid, muscles, also to the buccinator 

 muscle. The temporal muscle receives a large and appropriate nerve. The 

 nerve to the masseter passes between the coronoid and condyloid processes 

 of the lower jawbone ; but before going into the muscle it sends branches to the 

 temporal muscle. The pterygoid muscles have each their appropriate nerves 

 coming direct from this plexus. 



Ramus Buccinalis Labialis. 



This is a remarkable branch which arises from the same source, and goes to 

 the cheek and lips. This nerve where it lies on the external pterygoid muscle 

 sends one more branch to the temporal muscle ; it then divides, one branch 

 enters the buccinator muscle, and another is prolonged forwards. The division 

 to the buccinator muscle is tortuous, which is no doubt a provision for its 

 being undistui'bed by the free motion of the cheek ; its minute branches may 

 be traced until lost among the muscular fibres, whilst others penetrate to the 

 lining of the cheek. The prolonged branch is the labial division; it runs 

 nearer the alveolar processes of the lower jaw, and becomes so superficial as 

 to admit a union with the portio dura : from thence passing under the facial 

 artery it may be traced into the triangularis or depressor anguli oris, the levator 

 labiorum communis, and the lateral portion of the orbicularis oris. 



In the distribution of the buccinalis labialis to the muscles of the mouth, it 

 is joined, as I have said, by branches of the portio dura ; and nothing is more 

 striking than the manner in which this latter nerve passes over the masseter, 

 a muscle of the jaw, to be profusely given to the muscles of the lips. 



There is one more branch important to the physiology of the fifth nerve. 

 At the root of the mandibulo-labralis (where it is sent off from the junction of 

 the muscular and ganglionic portions), a small nerve takes its origin. This 

 branch runs parallel to the greater nerve till it enters the foramen in the lower 

 jaw ; here it seems to enter, but does not ; it takes a course on the inside of 

 the jaw to arrive at its final destination, the mylo-hyoideus and the anterior 

 belJy of the digastricus, that is, to those muscles which open the mouth by 

 drawing down the jaw. 



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