328 



HEAD AND NECK 



Nervus Trigeminus. The two roots of this nerve have 

 already been seen piercing the dura mater at the apex of 

 the petrous portion of the temporal bone under the anterior 

 margin of the tentorium. Now that the dura mater has been 

 raised from the lateral part of the middle cranial fossa, the 

 further relations of these nerve-roots within the cranium may 

 be studied. It will be noticed that the loosely connected 



Levator palpebrae superioris 

 Superior rectus 



Superior oblique 



Lacrimal gland 



Lateral rectus 



Sixth nerve 



Ciliary ganglion 

 Naso-ciliary nerve 



Ophthalmic division 



of fifth nerve 



Maxillary division 



of fifth nerve 



Motor root of 

 fifth nerve 



Semilunar ganglion / 



Mandibular division of fifth nerve 



Trochlea 



"** I Superior oblique 



Inferior rectus 

 Medial rectus 



Fourth nerve 

 Sixth nerve 



Optic nerve 



Third nerve 



Sixth nerve 

 Fourth nerve 



FIG. 131. Dissection of the Orbit and the Middle Cranial Fossa. Both 

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



and parallel funiculi of the portio major^ or sensory root, at 

 once begin to divide and join with each other so as to 

 form a dense plexiform arrangement, whilst, at the same time, 

 the nerve-root increases somewhat in breadth. The interlace- 

 ment, thus brought about, occupies the smooth depression 

 which marks the anterior aspect of the apex of the petrous 

 portion of the temporal bone, and it sinks into the semilunar 

 ganglion (O.T. Gasserian). 



