lis OUTLINES OF EQUINE ANATOMY. 



the lip, and so gains tlie incisive foramen, where it combines 

 with the corresponding artery from the opposite side, and 

 the trunk thus formed joins with the arch formed by the 

 union of the two palatine arteries, which run along the 

 sides of the roof of the mouth. The facial artery runs 

 upwards, anastomosing with branches of the ocular arteries, 

 which bend round the margin of the orbit. At its upper 

 part it passes over the origin of nasalis longns labii 

 superioris (which arises from about the point of junction 

 of the nasal, malar, and lachrymal bones). 



By removal of zygomaticus and retractor anguli oris we 

 expose buccinator and caninus. These two muscles are 

 intimately blended ; buccinator anteriorly blends with 

 orbicularis oris, its fibres run directly backwards to become 

 inserted into the anterior margin of the ramus of the lower 

 jaw, posteriorly to the alveolar cavities ; it is also attached 

 slightly to the alveolar ridges and to the tuberosity of the 

 superior maxilla. To show this an incision must be made 

 through masseter externus, whereby it will be found to 

 cover superiorly a varicose vein situated immediately 

 beneath the zygomatic spine, running from the submaxil- 

 lary vein on the cheek through the foi-amen lacerum orbi- 

 tale to the cavernous sinus ; below this is one of the buccal 

 salivary glands from two to three inches in length, similar 

 in structure to the parotid gland, the secretion of which is 

 poured into the mouth through numerous foramina opening 

 upon a line of papillary eminences of the buccal mucous mem- 

 brane, opposite to the upper molar teeth. Below this gland 

 is seen buccinator intimately blended with retractor labii 

 inferioris, inserted as above mentioned. Caninus is com- 

 posed of two distinct layers of arched fibres, which arise 

 from the superior and inferior maxillary bones respectively 

 at the interdental spaces, run towards the central line of 

 the anterior part of buccinator, where they blend together 

 and with that muscle, sending some straight fibres to blend 

 with it posteriorly. By raising the infero-anterior part of 

 buccinator, just in front of masseter externus, we expose 

 the inferior buccal glands, in every respect, except situa- 

 tion, resembling the superior ; they lie in immediate con- 

 tact with the buccal mucous membrane, with which the 

 internal surface of buccinator is intimately attached 

 throughout the rest of the cheek. Passing around the 

 anterior margin of the coracoid process of the inferior max- 



