982 



THE NERVE SYSTEM 



apex of the petrous portion of the temporal bone. The ganglion is of somewhat 

 crescentic form, with its convexity turned forward. Its upper surface is intimately 

 adherent to the dura. Besides the small or motor root, the large superficial petrosal 

 nerve lies underneath the ganglion. 



OCULOMOTOR TROCHLEAR ABDUCEN9 

 NERVE NERVE NERVE 



MOTOR PORTION 

 OF FIFTH NERVE 



-SENSOR PORTION 

 OFTRIGCMINAL NERVE 



SEMILUNAR NERVE 



(Gasserian ganglion) 



MANDIBULAR 

 NCRVE 



SENSOR ROOT 

 VIDEO 



FIG. 731.- The right semilunar or Gasserian ganglion, viewed from the medial side. (Spdjmholz.) 



Branches of Communication. This ganglion receives on its inner side filaments 

 from the carotid plexus of the sympathetic. 



Branches of Distribution. It gives off minute branches to the tentorium cerebelli 

 and the dura in the middle fossa of the cranium. From its anterior (conre.r) 

 border, which is directed forward and outward, three large branches proceed 



the ophthalmic, superior maxillary, and 

 inferior maxillary. The ophthalmic, 

 and superior maxillary consist exclu- 

 sively of fibres derived from the large 

 root and ganglion, and are s< 'ely 

 nerves of common sensation. 

 ihird division, or inferior maxillary. 

 is joined outside the cranium by the 

 motor root, and is, therefore, strict Jy 

 speaking, the only portion of the tri- 

 geminal nerve which can he said to' 

 resemble a spinal nerve. 



Associated with the three division^ 

 of the trigeminal nerve are four small 

 gangliathe ophthalmic, sphenopala^ 

 tine, otic, and submaxillary ganglia. 



The ophthalmic nerve (u. ophtlial- 

 micus), or first division of the tri- 

 geminal, is a^ensorjierye. It supplies 

 sensor branches to the cornea, ciliary 

 muscle, and iris, to the lacrimal gland, 

 to a part of the mucous lining of the nasal fossae, and to the integument of the 

 eyelids, eyebrow, forehead, and nose (Fig. 737). It is the smallest of the three 

 divisions of the fifth, arising from the upper part of the Gasserian ganglion. It 

 is a short, flattened band, about 2 cm. (-| inch) in length, which passes forward 



SUPERIOR 

 PETROSAL SINUS 



ACIAL AND 



NERVES 



" 



