DISSECTING MANUAL. 



pierces the free border of the tentoriuni external to the oculo- 

 motor and runs below it in the outer wall of the cavernous 

 sinus, and then runs through the sphenoidal fissure above the 

 ocular muscles. [675-677] 



The trigeminal roots both pierce the dura beneath the petrous 

 attachment of the tentorium. The large (sensory) root de- 

 velops a large ganglion (Gasserian) in a depression at the apex 

 of the petrous bone. Three branches arise from the front of 

 the ganglion, viz.: the ophthalmic, which runs in the outer 

 wall of the cavernous sinus below the trochlear and divides in 

 the sphenoidal nssure into three branches, lachrymal, frontal, 

 and nasal ; the superior maxillary, which runs below the cav- 

 ernous sinus and through the foramen rotundum; and the 

 inferior maxillary, which runs through the foramen ovale. The 

 small (motor) root runs under the ganglion and through the 

 foramen ovale. [678] 



The abducent pierces the dura beside the dorsum sellae, runs 

 on the inner wall of the cavernous sinus, external to the carotid 

 artery, and then continues lowermost through the sphenoidal 

 nssure. The facial, with the pars intermedia below it, runs 

 through the internal auditory meatus and into the aqueduct 

 of Fallopius. The auditory runs through the internal audi- 

 tory meatus below the facial and pars intermedia and divides 

 into two trunks. Its upper (vestibular) trunk is continuous 

 with the mesial root, gets fibres from the pars intermedia, 

 sends a branch to the geriiculate ganglion, and splits into three 

 branches which run through the lamina cribrosa to the utricle 

 and the superior and external semicircular canals. Its in- 

 ferior (cochlear) trunk is continuous with the lateral root, 

 sends branches to the saccule and posterior semicircular canals, 

 and runs (cochlear nerve) through the lamina cribrosa to the 

 modiolus and spiral lamina of the cochlea. [686-688] 



The glosso-pharyngeal runs through the jugular foramen in 

 the anterior dural compartment. The pneumogastric and 

 spinal accessory run through the jugular foramen in the dural 



[46] 



