314 



FUNCTIONS OF THE NERVOUS SYSTEM. 

 Fig. 153. 



The distribution of the Facial jierve, 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 

 (f>) the infra-orbital nerve. 7. Facial branches, communicating with (S) the mental nerve. 9. Cervico- 

 facial branches, communicating 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 anserinus. 12. The auricularius 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 superficial 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. 16. 

 The occipitalis major nerve, the posterior branch of the second cervical nerve. 



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. 



a. The distinctness of the Spinal and Encephalic actions of this nerve, is made evident 

 by the not unfrequent 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 ; so 

 that, 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 tension 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 j in con- 

 sequence of paralysis of the Cerebral portion of the nerve on one side. 



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

 alluded to in part ; but there still remain several questions to be discussed in 

 regard to them. Reasons have been given for the belief that it is chiefly an 

 afferent nerve, scarcely having any direct power of exciting muscular con- 

 traction, but conveying impressions to the Medulla Oblongata, which produce 

 reflex movements of the other nerves ( 384). This view of its function has 

 been deduced by Dr. Reid from minute anatomical investigation, and from a 

 large number of experiments. Some experimenters assert, that they have 

 .succeeded in exciting direct muscular actions through its trunk ; but these ac- 

 tions seem to be limited to the stylo-pharyngei and to the palato-glossi mus- 



