318 



THE MUSCLES OF THE DOG 



THE MUSCLES OF THE DOG 

 Muscles of the Face 



The panniculus carnosus is well developed and presents two distinct bands, 

 one of which is inserted into the lower lip, the other into the scutiform cartilage of 

 the ear. 



The orbicularis oris is poorly developed. In the upper lip it is divided cen- 

 trally, and in the lower it is distinct only near the angles of the mouth. 



The levator nasolabialis is wide and undivided, and ends in the upper lip. 



The levator labii superioris proprius arises behind the infraorbital foramen, 

 runs forward under the preceding muscle, and ends in numerous small tendons 

 around the nostril, some blending with those of the opposite side. 



The zygomaticus, long and narrow, arises on the scutiform cartilage, and 

 ends at the angle of the mouth. 



Fig. 229. — Muscles of Head of Dog 

 a, Scutularis; b, c, anterior auricular muscles; d, helicis; e, antitragicus; /, /, zygomaticus, out of which 

 a portion is cut; g, slip of panniculus; /(, parotiJo-auricularis; i, masseter; k, malaris; I, levator nasolabialis; 

 m, levator labii superioris proprius; n, dilatator naris lateralis; o, p, buccinator (buccalis, molaris); q, retractor 

 anguli oris; r, digastricus; s, mylo-hyoideus; 7, base of concha; ^, parotid gland; ;2', parotid duct; 5, submaxil- 

 lary gland; 4< submaxillary lymph glands; 5, buccal glands; 6, zygomatic arch; 7, maxilla; S, dorsum nasi; 

 9, parotid lymph gland. (EUenberger-Baum, Anat. d. Hundes.) 



The depressor labii inferioris is absent, unless we recognize as such a thin 

 stratum arising on the body of the mandible and spreading out in the orbicularis. 



There are no special nasal muscles, the homologue of the lateral dilator ending 

 almost entirely in the upper lip. 



The buccinator is wide and very thin, and the two planes of fibers cross each 

 other. 



The palpebral muscles present no very noteworthy special characters. 



MUSCLES OF MASTICATION 



The masseter is large. It arises from the zygomatic arch, and extends beyond 

 the branch of the jaw below and behind. Three strata may be recognized in its 

 structure. 



The temporalis is very large and strong, and contains much tendinous tissue. 

 It arises from the temporal fossa and the orbital ligament. 



