550 BLOOD-VASCULAR SYSTEM OF THE HORSE 



(5) The superior labial artery (A. laliialis superior) arises from the facial in 

 front of the facial crest (Fig. 435 j . It passes forward under the dilatator naris lat- 

 eralis and levator nasolabialis to the upper lip, gives twigs to the upper part of tiie 

 cheek and the lateral nasal region, and ramifies in the upper lip, anastomosing with 

 the opposite artery and the palato-labial. 



(6) The lateral nasal artery (A. lateralis nasi) arises usually a little above the 

 preceding one, and runs forward parallel with it and imder the levator nasolal)ialis 

 to the nostril (Fig. 435). It supplies branches to the lateral nasal region and the 

 nostril. 



The vessel is often double. It may arise from the superior lal)ial at the point of bifurcation 

 of the facial or with the dorsal nasal from the infraorbital artery (as in the oxj. In some cases 

 it gives off a dorsal nasal branch. 



(7) The dorsal nasal artery (A. dorsalis nasi) arises on the levator laliii superi- 

 oris proprius and passes forward laider the levator nasolabialis to the dorsum nasi 

 (Fig. 435). 



(8) The angular artery of the eye (A. angularis oculi) runs toward the internal 

 canthus of the eye, where it anastomoses with the orl;)ital branch (Ramus malaris) 

 of the infraorbital artery (Fig. 435) . 



In addition to the preceding, unnamed branches are supplied to the submaxil- 

 lary salivary gland and the submaxillary lymph glands. 



3. The posterior auricular artery (A. auricularis posterior) arises at an acute 

 angle from the external carotid just above the origin of the masseteric. It passes 

 upward under cover of the parotid gland, to which it gives branches, and divides 

 into several branches which supply the skin and muscles of the external ear (Fig. 

 435) . The posterior branch passes to the posterior part of the base of the ear, 

 where it divides into two branches; of these, one (Ramus intermedins) passes up the 

 convex surface of the external ear to the apex, while the other (Ramus medialis) 

 winds around to the anterior (inner) border, and forms an arch with the inter- 

 mediate branch. The external branch (Ramus lateralis) passes up the posterior 

 (external) border of the ear and forms an arch with the intermediate branch. 

 The deep branch (A. auricularis profunda) enters the interval between the exter- 

 nal auditory canal and mastoid process, and passes through an opening into the 

 interior of the external ear and ramifies in the skin which lines it. It gives off the 

 stylomastoid artery, which passes through the stylomastoid foramen into the tym- 

 panum, forms an arch around the membrana tympani, and supplies the middle ear 

 and its muscles. 



THE SUPERFICIAL TEMPORAL ARTERY 



This artery (A. temporalis superficialis) is much the snuiller of the two terminal 

 branches of the external carotid. It passes upward behind the posterior border of 

 the ramus of the mandible under cover of the parotid gland, and divides below 

 the level of the condyle into the anterior auricular and transverse facial arteries. 

 It is crossed superficially by the facial nerve. 



The anterior auricular artery (A. auricularis anterior) passes upward l^ehind 

 the temporo-mandibular articulation under cover of the parotid gland, crosses the 

 zygomatic arch, and reaches the temporalis muscle. It is crossed deeply at its 

 origin by the superficial temporal nerve and is accompanied by a satellite vein 

 and the auriculo-palpebral ])ranch of the facial nerve. It is distributed to the 

 skin and the temporal and anterior auricular muscles, and sends a branch through 

 the conchal cartilage to the skin which lines it. Collateral twigs are detached to 

 the parotid gland, and an anterior branch anastomoses with the supraorbital 

 artery. A ]:>ranch sometimes passes into the parieto-temporal canal and anasto- 

 moses with the posterior meningeal (mastoid) artery. 



The transverse facial artery (A. transversa faciei) is larger than the preceding. 



