LATERAL PART OF MIDDLE CRANIAL FOSSA 237 



arrangement, whilst, at the same time, the nerve-root increases 

 somewhat in breadth. The interlacement, 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). 



M. levator palpebrse superioris 

 M. rectus superior 



M. obliquus superior 

 Lacrimal gland 



M. rectus lateralis 



Sixth nerve 



Ciliary ganglion 

 Naso-ciliary nerve 



Ophthamic division 

 of trigeminal nerve 

 Maxillary division 

 of trigeminal nerve 



Motor root of 

 trigeminal nerve 



Semilunar ganglion/ / 



Trochlea 



M. obliquus 

 superior 



M. rectus 

 inferior 



M. rectus medialis 



- Trochlear nerve 

 Abducens nerve 



Optic nerve 



Oculo-motor 



| 'nerve 



Abducens nerve 

 Mandibular division of trigeminal nerve Trochlear nerve 



FIG. 87. Dissection of the Orbit and the Middle Cranial Fossa. Both 

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



The Semilunar Ganglion (O.T. Gasserian) is somewhat 

 crescentic in form. It lies upon the sutural junction between 

 the apex of the petrous bone and the great wing of the 

 sphenoid bone. There it is enclosed within a recess or space, 

 called the cavum Meckelii, formed by a separation of the two 

 layers of the dura mater. The concavity of the ganglion is 

 directed postero-medially, and it is upon that aspect that it 

 receives the interlacing fibres of the sensory root of the 

 trigeminal nerve ; the convexity of the ganglion is directed 



