110 EQUINE ANATOMY. 



the eye as the retina. They are exclusive to the sense 

 of sight. , ^ 



3. Common oculo motor. — Emanates from the cere- 

 bral peduncles near the peduncular fissure by eight 

 branches. Course : The single trunk of the nerve runs 

 outwards to the smallest supra sphenoidal canal, passes 

 through the orbital liiatus, and ramifies in the muscles 

 of the eye, except the external and posterior recti and 

 the great obliqiie. Functions : Essentially motor. 



4. Fathetic^rinternal oculo motor. — Kises from 

 the band of E,eil behind the corpora quadrigemina by 

 two roots. Its course is outwards, downwards and for- 

 wards to reach the smallest of the susphenoidal canak, 

 penetrate the- outer sheath and ramify in the great 

 oblique muscle of the eye. Functions : Motor. 



5. Trigemini or trifacial. — Is a mixed nerve, hav- 

 ing an external root, sensitive, and an internal, motor. 



Sensitive root. — The largest comes from the an- 

 nular protuberance ; it runs forward and downwards 

 to the occipito-spheno-temporal hiatus, and terminates 

 in the Gasserian ganglion. This ganglion is crescent 

 shape, and situated in the cartilaginous substance 

 which closes the foramen lacerum ; it gives origin to 

 two branches, one passes out of the cranium, the other 

 is lodged in the external fissure of the cranial face of 

 the sphenoid and bifurcates; thus at its origin is divided 



