THE NERVOUS SYSTEM OF THE DOG 



851 



buccal nerve, and ramifies on the lateral surface of the face. The inferior alveolar 

 nerve arises by a common trunk with the mylo-hyoid; it gives off dental branches 

 and termmates m mental and inferior labial branches. The lingual nerve supplies 

 vaso-dilator and excito-secretory filaments to the mandibular and sublingual 

 salivary glands; these fibers are derived from the chorda tympani. 



The facial nerve divides near the posterior border of the jaw into four branches. 

 The upper branch is the auriculo-palpebral nerve, which divides after a very short 

 course into anterior auricular and zygomatic branches. The latter curves upward 

 and forward across the zygomatic arch toward the eye, and divides into branches 

 which supply the eyelids and nasal region and concur with the frontal and lacrimal 

 nerves in forming the anterior auricular plexus. The superior buccal nerve ac- 

 companies the parotid duct across the masseter. The inferior buccal nerve runs 

 forward along the lower border of the masseter and the mandible. The two nerves 



Fig. 682. — Deep Dissection of Head of Dog, Showing Especially Thigeminal and Hypoglossal Nerves. 

 a, Hypoglosaal nerve; 6, cervical branch of a; c, mandibular division of trigeminus; d, lingual nerve; e, nerve to 

 mandibular gland; /, deep temporal nerve; g, pterygoid nerve; h, buccinator nerve (cut); i, inferior alveolar nerve; 

 k, staphyline branch of lingual nerve; I, chorda tympani; m, mylo-hyoid nerve; n, sphenopalatine nerve; o, lesser 

 palatine nerve; p, great palatine nerve; g, infraorbital nerves; r, n. subcutaneus malae; s, branch of oculomotor nerve 

 to inferior oblique muscle ; £, lacrimal nerve; u, frontal nerve; d, trochlear nerve; uj, abducens nerve; i, carotid artery; 

 ^.lingual artery; 5, internal naaxiUary artery; 4, ni. thyro-pharyngeus; 5, m. hyo-pharyngeus; 5, m. thyro-hyoideus; 

 7, m. sterno-hyoideus; 8, m. hyo-glossus; 9, m. genio-hyoideus; 10, m. genio-glossus; 11, m. stylo-glossus ; 1^, m. 

 pterygoideus medialis; 13, outline of mandibular gland (dotted) ; 14, atlas; 15, bulla ossea; 16, zygomatic arch (dotted) ; 

 17, m. rectus oculi inferior; 18, m. obliquus oculi inferior. (EUenberger-Baum, Anat. d. Hundes.) 



ramify on the cheek and anastomose with each other and the infraorbital nerves 

 to form a plexus from which branches go to the muscles of the lips and nostrils. 

 The cervical branch runs downward and backward over the mandibular gland 

 and ramifies in the cervical cutaneus muscle; it communicates with the inferior 

 buccal nerve and sends twigs to the parotido-auricularis muscle and the mandibular 

 space. 



The vagus bears a jugular ganglion and a ganglion nodosum. The former is 

 situated on the nerve just before the emergence of the latter from the cranium. The 

 latter is situated near the anterior cervical ganglion on the rectus capitis ventralis 

 major and dorsal to the internal carotid artery; it is fusiform and may be about half 

 an inch (ca. 1-1.5 cm.) long in a large dog. In its course in the neck the nerve is 

 inclosed with the sympathetic trunk in a common sheath and is related ventrally 



