Cranial Nerves. 



125 



GlaruL 

 lacrym. 



GANCL. &ASSERI 



V N. TRIGEMItJ 



Lamina 

 crlbrosa 



PLEX. CAROTIC. 



N. OCULOMOTOR. 



iv. N. TROCHLEAR; 



VI. N.ABDUCENS 



469. The Oculomotor, Trochlear and Abducent 



Nerves. View from above. 



The third pair of cranial nerves, the oculomoto r, kermis oculo- 

 motorius, emerges from the Cms cerebri close to the Pons Varolii, runs 

 obliquely forwards and outwards, and becomes imbedded in the upper 

 wall of the cavernous sinus (here it receives some filaments from the 

 cavernous plexus of the sympathetic nerve). It then divides into two 

 branches which enter the orbit through the sphenoidal fissure. The smaller 

 superior division, Eamus superior, supplies the M. levator palpebrae superioris 

 and the M. rectus superior; the larger inferior, Ramus inferior, divides into 

 three branches for the M'. rectus interims, M. rectus inferior and j\L obliquus 

 inferior. From the latter, the longest branch, a short thick twig is given off 

 to the ciliary ganglion, forming its inferior root, Radix brevis s. motoria. 



The fourth, trochlear or pathetic nerve, Nervus trocldearis 

 s. patheticus, is the smallest of the cranial nerves. It arises immediately 

 behind the Corpus quadrigeminum, winds around the Processus cerebelli ad 

 corpus quadriyeminum and the Pedunculus cerebri, pierces the dura mater 

 behind the posterior clinoid process and is here united with the ophthal- 

 mic division of the fifth nerve. It then enters the orbit through the 

 sphenoidal fissure and passes inwards to the M. obliquus superior. 



17* 



