258 



HEAD AND NECK 



Nervus Oculomotorius. The two divisions of the oculo- 

 motor nerve enter the orbit through the superior orbital 

 fissure, between the two heads of the lateral rectus. The 

 superior division has been traced to the rectus superior and 

 the levator palpebrae superioris. The inferior division is 

 larger. It almost immediately divides into three branches, 



M. levator palpebrae superior 

 M. rectus superior 



M. obliquus superior 

 Lacrimal gland 



M. rectus lateralis 



Abducens nerve 



Ciliary ganglion 

 Naso-ciliary nerve 



Ophthalmic division 

 of trigeminal nerve r 

 Maxillary division 

 of trigeminal nerve 



Motor root of 

 trigeminal nerve 



Semilunar ganglion ' / 



Mandibular division of fifth nerve 



Trochlea 



M. rectus inferior 



Trochlear nerve 

 Abducens nerve 



Optic nerve 



1 \ Oculo-motor 



| \nerve 



Abducens nerve 

 Trochlear nerve 



FIG. 97. Dissection of the Orbit and the Middle Cranial Fossa. Both 

 roots of the fifth nerve, with the semilunar ganglion, are turned laterally. 



for the supply of the rectus medialis, the rectus inferior, and 

 the obliquus inferior. The nerves to the two recti enter the 

 ocular surfaces of the muscles ; the nerve to the inferior 

 oblique is prolonged forwards, in the interval between the 

 rectus inferior and rectus lateralis, and enters the posterior 

 border of the inferior oblique muscle. Soon after its origin 

 this branch gives the short motor root to the ciliary ganglion. 



Nervus Abducens. The abducens nerve will be found 

 closely applied to the ocular surface of the lateral rectus. It 



