170 FUNCTIONS OF THE NERVOUS SYSTEM. 



Fig. 38. 



The distribution of the Facial Nerve, and the branches of the Cervical Plexus; 1, the facial nerve, 

 escaping from the stylo-mastoid foramen, and crossing the ramus of the lower jaw; the parotid gland has 

 been removed in order to see the nerve more distinctly ; 2, the posterior auricular branch; the digastric 

 and stylo-mastoid filaments are seen near the origin of this branch ; 3, temporal branches, communicating 

 with (4) the branches of the frontal nerve; 5, facial branches, communicating with (6) the infra-orbital 

 nerve; 7, facial branches, communicating with (6) the mental nerve; 9, cervico-facial branches, commu- 

 nicating with (10) the superficialis colli nerve, and forming a plexus (11) over the sub-maxillary gland ; the 

 distribution of the branches of the facial in a radiated direction over the side of the face, constitutes the 

 pes anserimus; 12, the auricularis magnus nerve, one of the ascending branches of the cervical plexus ; 

 13, the occipitalis minor, ascending along the posterior border of the sterno-mastoid muscle ; 14, the super- 

 ficial and deep-descending branches of the cervical plexus ; 15, the spinal accessory nerve, giving off a 

 branch to the external surface of the trapezius muscle : 10, the occipitalis major nerve, the posterior 

 branch of the second cervical nerve. 



and thus sensory fibres are introduced into it from many different sources 

 anteriorly, from the Fifth pair; and posteriorly, from the Cervical nerves 

 which cause irritation of several of its branches to produce pain. The number 

 and situation of the anastomoses vary much in different animals ; so that it is 

 impossible to make any very comprehensive statement in regard to them. 

 Experimental researches leave no doubt that the Portio Dura is the general 

 motor nerve of the face, ministering to the influence of Volition and of Emo- 

 tion, and also being the channel of the Reflex movements concerned in respi- 

 ration and other associated movements of the muscles, but not being in the least 

 concerned in the act of mastication.* 



228. The functions of the Glosso-Pharyngeal nerve have been heretofore 



* The distinctness of the Spinal and Cerebral portions of this nerve is made evident 

 by the not nnfrequent occurrence of paralysis in either of them, without the other being 

 affected. Thus we may see the mouth 'drawn to one side (in consequence of the loss of 

 tone which the muscles have experienced), and all the Reflex and Emotional actions of 

 the face performed only on one side; and yet Voluntary power may remain unaffected. 

 Thus, in ordinary winking, the lid of the affected side does not close, though the patient 

 can shut the eye by an effort of the will. On the other hand, the tone of the muscles 

 may remain unimpaired, and all their Reflex and Emotional actions may be performed 

 as usual, and yet distortion may be at once apparent, when Voluntary actions are 

 attempted, in consequence of paralysis of the Cerebral portion of the nerve on one side. 



