496 SIXTH PAIR OF NERVES. 



of the superior maxillary. The descending also sends branches 

 to the external ear ; it supplies the parotid gland, and com- 

 municates with the inferior dental and auricularis magnus 

 nerve. 



The Sixth Pair of Nerves, 



Are called Motores Externi. They arise from the com- 

 mencement of the medulla oblongata, and proceed forward 

 under the pons Varolii. They proceed through the dura mater 

 on the inside of the fifth pair; they appear to pass through the 

 cavernous sinuses, but are enclosed in sheaths of cellular mem- 

 brane while they are in those sinuses. When in this situation 

 they are near the carotid arteries, and each nerve sends off one 

 or more very fine twigs, which being joined by a twig from 

 the pterygoid .branch of the fifth pair, descend along the carotid 

 artery through the carotid canal, and then unite themselves to 

 the upper extremity of the upper cervical ganglion of the 

 intercostal nerve. 



The sixth pair afterwards pass into the orbit of the eye, 

 each through the foramen lacerum of its respective side, and is 

 spent upon the Rectus Externus or Abductor muscle of the eye. 



The Seventh Pair of Nerves 



Comprises two distinct cords, which have very different des- 

 tinations ; and have, therefore, been considered as different 

 nerves, by several anatomists. One of these cords is appro- 

 priated to the interior of the ear, and is the proper Auditory 

 Nerve. The other is principally spent upon the face, and, 

 therefore, has been called the Facial. They have, however, 

 more frequently been denominated the Seventh Pair, and dis- 

 tinguished from each other, in consequence of a great differ- 

 ence 'in their texture by the appellations of Portio Dura and 

 Portio Mollis. 



These two cords pass off nearly in contact with each other, 

 from the side of the upper part of the Medulla Oblongata, 

 where it is in contact with the pons Varolii ; but the Portio 

 Mollis can be traced to* the fourth ventricle, while the Portio 

 Dura is seen to come out from the union of the pons Varolii 



