FACIAL NERVE. 



401 



buted in company with the branches of the temporal artery. In its course 

 it sends filaments to the temporo-maxillary articulation, to the pinna and 

 meatus of the ear, and to the integument in the temporal region. It com- 

 municates on the temple with branches of the facial, supra-orbital, lachry- 

 mal, and subcutaneus malae nerve. The descending branch enters the 

 parotid gland, to which it sends numerous branches ; it communicates 

 with the inferior dental and auricularis magnus nerve, and supplies the 

 external ear, the meatus auditorius, and the temporo-maxiilary articulation, 

 and sends one or two filaments into the tympanum. 



SIXTH PAIR. ABDUCENTES. The abducens nerve, about half the size 

 of the motor oculi, arises by several filaments from the upper constricted 

 part of the corpus pyramidale close to the pons Varolii. Proceeding for- 

 wards from this origin it lies parallel with the basilar artery, and, piercing 

 the dura mater upon the clivus Blumenbachii of the sphenoid bone, ascends 

 beneath that membrane to the cavernous sinus. It then runs forwards 

 along the inner wall of the sinus below the other nerves, and, resting 

 against the internal carotid artery, passes between the two heads of the 

 external rectus, and is distributed to that muscle. As it enters the orbit, 

 it lies upon the ophthalmic vein, from which it is separated by a lamina 

 of dura mater. In the cavernous sinus it is joined by several filaments 

 from the carotid plexus, by one from MeckePs ganglion, and one from the 

 ophthalmic nerve. Mr. Mayo traced the origin of this nerve between the 

 fasciculi of the corpora pyramidalia to the posterior part of the medulla 

 oblongata ; and Mr. Grainger pointed out its connexion with the grey 

 substance of the spinal cord. 



SEVENTH PAIR. The seventh pair consists of two nerves which lie side 

 by side on the posterior border of 



the crus cerebelli. The smaller and ^ ig- 181> * 



most internal of these, and, at the 

 same time, the most dense in tex- 

 ture, is the facial nerve or portio 

 dura. The external nerve, which 

 is soft and pulpy, and often grooved 

 by contact with the preceding, is 

 the auditory nerve or portio mollis 

 of the seventh pair. Soemmering 

 makes the auditory nerve the eighth 

 pair; but, retaining the classifica- 

 tion of Willis, we regard it as 

 a part of the seventh with the 

 facial. 



FACIAL NERVE (portio dura). The facial nerve arises from the 'jpper 

 part of the groove between the corpus olivare and corpus restiforme, close 

 to the pons Varolii, from which point its fibres may be traced deeply into 

 the corpus restiforme. The nerve then passes forwards, resting upon the 



* A view of the origin and distribution of the portio nrollis of the 7th pair or auditory 

 nerve. 1. The medulla oblongata. 2. The pons Varolii. 3 and 4. The crura cerebelfi 

 of the right side. 5. 8th pair. 6. 9th pair. 7. The auditory nerve distributed to tlm 

 cochlea and labyrinth. 8. The 6th pair. 9. The portio dura of the 7th pair. 10. Th 

 4*Ji pair. 11. The 3d pair. 



34* SA 



