THE TRIGEMINAL NERVE. 



1235 



f. The infratrochlear nerve (n. infratrochlearis) (Fig. 1058) runs forward along the inner 

 orbital wall and beneath the superior oblique muscle and its pulley to the inner end of the pal' 

 pebral fissure, where it terminates. Near the pulley it receives a filament (the supratrochlear) 

 from the frontal nerve. It supplies the skin of the upper eyelid and root of the nose, as well as 

 the conjunctiva and the lachrymal caruncle and sac. 



d. The internal nasal or septal branch (rr. mediates) (Fig. 1048) supplies the mucous mem- 

 brane of the anterior portion of the septum. 



e. The external nasal branch (rr. laterales) (Fig. 1047) supplies the front part of the middle 

 and inferior turbinate bones and outer wall of the nasal fossa. 



f. The anterior nasal branch (r. nasalis extremus) passes downward in a groove in 

 the under side of the nasal bone and then between the lower end of the nasal bone and the 



FIG. 1057. 



Superior oblique muscle. > 

 Internal rectus muscle^ ( 



Infratrochlear br. of nasal 

 Nasal nerve 



Olfactory bul 



Leva tor palpebne superi- 

 oris, inverted 



III. nerve, superior 

 division' 



Frontal nerv 

 Optic nerve 



Internal carotid artery 5 



III. nerv 



Pons, displaced backward 



Cerebral peduncle- 



Levator palpebrse superiorts 

 Superior rectus 



Lachrymal gland 

 Nerve to inferior oblique 

 External rectus muscle 



Ciliary ganglion 



Nasal nerve 

 Lachrymal nerve 



Maxillary division of V. 

 Ophthalmic division of V 

 Mandibular division of V 

 asserian ganglion 



VI. nerve 

 IV. nerve 



VII. nerve 



VIII. nerve 



Deeper dissection of right orbit, viewed from above ; branches of nasal nerve shown. 



upper lateral cartilage of the nose, finally emerging from under cover of the compressor naris 

 muscle. It supplies the skin of the fore-part and tip of the nose. 



Variations. The nasal nerve may send branches to the superior and internal recti and 

 levator palpebrae superioris muscles. In one case a small ganglion connected with the nasal 

 nerve sent fibres to the third and sixth nerves. Instances are recorded of absence of the 

 infratrochlear branch, the deficiency being supplied by the supratrochlear. Branches to the 

 frontal and ethmoidal sinuses are described as being given off in the anterior ethmoidal fora- 

 men, and a branch has been found which passes through the posterior ethmoidal foramen to 

 supply the sphenoidal and posterior ethmoidal sinuses. The latter has been called by Luschka 

 the spheno- ethmoidal and by Krause the posterior ethmoidal branch. 



The Ganglia associated with the Trigeminal Nerve. Four small ganglia 

 are connected with the extracranial portion of the fifth nerve. They are the ciliary, the 

 spheno-palatine, the otic and the submaxillary. The ciliary ganglion is associated 



