326 



HITCHCOCK'S ANATOMY 



terior portion of the base of the brain, and are distributed 

 upon the mucous membrane of the nostrils ; especially that 

 part of it which is spread out upon the turbinated bones. 



Fig. 311. 584. Optic— The optic 



nerves arise at a point be- 

 hind that where the olfac- 

 tories are given off, and 

 about one inch from this 

 point come together and 

 form a ganglion ; after this 

 they are again separated and 

 proceed to the posterior 

 portion of each eye-ball 7 

 where they are expanded 

 into a membrane, called the 

 Ketina. (Fig. 311.) 



585. Motores Oculoi usi. 



— The third pair are also 

 given off from the base of 

 the brain near to the pons 

 varolii, and are sent to a 

 part of the muscles of the 

 eye. 



586. Trochlears.— The 

 trochleares have nearly the 

 same origin as the last-men- 

 tioned pair, and are distrib- 

 uted to the superior oblique 

 muscles of each eye. (Fig. 

 312.) 



587. Trifacial. -The fifth pair, or trifacial, is the largest 

 of the cranial nerves. It. is analogous to the spinal nerves in 



A View of the Second Pair or Optic, and 

 the Origin of Seven other Pairs. 1, 1, Globe 

 of the Eye. The one on the left hand is per- 

 fect, but that on the right has the Sclerotic 

 and Choroid removed to show the Retina. % 

 The Chiasm of the Optic Nerves. 3, The 

 Corpora Albicantia. 4, The Infundibulnm. 

 5, The Pons Varolii. 6, The Medulla Ob- 

 longata. The figure is on the Right Corpus 

 Pyramidale. 7, The Third Pair, Motores 

 Oculi. 8, Fourth Pair, Pathetici. 9, Fifth 

 Pair, Trigemini. 10, Sixth Pair, Abducentes. 

 11, Seventh Pair, Auditory and Facial. 12, 

 Eighth Pair, Pneumogastric, Spinal Acces- 

 sory, and Glosso-Pharyngeal. 13, Ninth Pair, 

 Hypoglossal. 



5S3. Give the anatomy of the olfactory nerves. 584. Describe the optic nerves. 555. 

 Describe the motores oculorum. 586. Give the anatomy of the fourth pair. 5S7. De- 

 scribe the trifacial. 



