256 



FASCIA AND MUSCLES OF THE HORSE 



Structure. — The muscle arises by a thin aponeurosis. The belly is also thin, 

 and divides into two branches, between which the lateral dilator of the nostril passes. 

 The dorsal branch reaches the nostril and upper lip, blending with the lateral di- 

 lator; the ventral one is much smaller, and blends at the labial commissure with 

 the orbicularis and buccinator. 



Relations. — Superficially, the skin, fascia, and lateral dilator (in part) ; deeply. 



Fig. 261. — Muscles of Head of Horse; Later.al View. 

 a, Levator labii superioris proprius; h, levator nasolabialis; 



The M. ctjtaxetis is Removed. 

 brachiocephalicus; d, sterno-cephalicus ; d\ 

 tendon of d; e, omo-hy oideus ; /, dilatator naris lateralis; p, zygomaticus; h, buccinator; i, depressor labii inferioris; 

 k, orbicularis oris; I, lateralis nasi, dorsal part; m, masseter; n, parotido-auricularis; o, zygomatico-auricularis; p, 

 interscutularis; p', fronto-scutularis, pars temporalis; y, cervico-auricularis profundus major; r, cervico-auricularis 

 superficialis; s, obliquus capitis anterior; /, splenius; ?;, occipito-mandibularis; y, mastoid tendon of brachiocephalicus; 

 i?, posterior, 3, anterior, border of external ear ; 5, seutiforni cartilage; 5, zygomatic arch ; iO, orbital fat; i5, temporo- 

 mandibular articulation; 27, facial crest; 30'. angle of jaw; 37. external maxillary vein; SS. jugular vein; 39, facial 

 vein; .^0, parotid duct; .^^, transverse facial vein; -i^, masseteric vein; 4^, facial nerve; .i.^, parotid gland; .^5, chin; 

 2, wing of atlas. By an oversight the superior buccal branch of the facial nerve is shown crossing over instead of under 

 the zygomaticus. (After EUenberger-Baum, Anat. fiir Kiinstler.) 



the levator labii superioris proprius, lateral dilator (in part), buccinator, branches 

 of the facial vessels and nerve, and the infraorbital artery and nerve. 



Blood-supply. — Facial and palato-labial arteries. 



Nerve-supply. — Facial nerve. 



3. Levator labii superioris proprius. — This lies on the dorso-lateral aspect of 

 the face, partly covered by the preceding muscle. 



Origin. — The lacrimal, malar, and maxillary bones at their junction. 



