126 OUTLINES OF EQUINE ANATOMY. 



to the appendages of the eye, also the su;pra-or'bital artery, 

 which passes iu a direction upwards to the root of the 

 orbital process of the frontal bone ; after passing through 

 the supra-orbital foramen it breaks up in sup"plying the 

 muscles of the forehead. A remarkable branch of this 

 artery, the lateral nasal makes a peculiar twist before 

 piercing the internal orbital foramen. By passing 

 through this it is described as gaiiiingthe nasal chamber, from 

 which it passes through the cribriform plate of the eth- 

 moid bone into the olfactory sinus, and after supplying 

 the olfactory bulb it passes again through the cribri- 

 form plate and supplies the mucous membrane of the 

 superior meatus of the nasal chamber. Some of the 

 ocular branches passing over the lower margin of the 

 orbit anatomose with branches of the facial artery. The 

 internal maxillary artery sends branches downward to 

 supply the soft palate, and the buccal branch to the cheek 

 and the molar glands ; it then breaks up into the spheno- 

 palatine, palato-maxillary, and superior dental branches. 



The spheno-palatine artery, passing through the foramen 

 of the same name, gains the nasal chamber, where it sup- 

 plies the inferior and middle meatus. The palato-maxillary 

 artery, on emerging from the palatine canal through the 

 palatine foramen, courses its way along the lateral part of 

 the hard palate, and bending inwards anteriorly is retained 

 in position by a small cartilaginous hook, and anastomoses 

 with its fellow, the arch so formed giving off a branch 

 which passes through foramen incisivum to anastomose 

 with the terminal parts of the superior labial arteries. The 

 superior dental artery passes through canalis infra orbitale, 

 and sends a branch to each molar ; it sends a small branch 

 through the infra-orbital foramen to anastomose with the 

 arteries of the face, but the main trunk runs between the 

 plates of the bones to supply the tush and the incisors. 



The fifth cranial nerve, pars trigemini, arises by two 

 roots from the lateral part of the pons Varolii at the 

 base of the brain. One of these is sensory, the other is 

 motor ; in this respect the nerve resembles those given off 

 from the spinal cord ; it is hence sometimes called the spinal 

 nerve of the brain, and the analogy is increased by the 

 presence of a large ganglion, the Gasserian, on the sensory 

 root. This ganglion is situated between the two folds of 

 dura mater, which constitute the membranous tentorium, 



