406 



DIGESTIVE SYSTEM OF THE HORSE 



glosso-pharyngeal, anterior laryngeal, and hypoglossal nerves, the mandibular 

 salivary gland, and the parapharyngeal lymph glands. 



The cavity of the pharynx (Cavum pharyngis) presents seven openings. 

 Through the posterior nares or choanae it communicates dorsally with the nasal 

 cavity. The pharyngeal orifices of the two Eustachian tubes (Ostia pharyngea 



Temporal muscle 



Nerves III, 

 IV, VI, and 

 ophthahnic 

 Internal max- 

 illary artery 

 Transverse 

 facial nerve 

 Buccinator- 

 nerve 

 Inferior al- 

 veolar nerve 



Inferior al- 

 veolar artery 



Great cornu of. 

 hyoid bone 



Lingual hranch 



of IX ?ierve 

 External max- 

 illary artery 

 Hypoglossal 

 nerve 



Masseteric. 

 • vesseli 



Thyroid cornu 

 of hyoid hone 



Coronoid process 



Transverse fa- 

 cial vessels 



Trmisverse fa- 

 cial nerve 



Lateral ptery- 

 goid muscle 



Internal maxil- 

 lary vein 



Medial pteryoid 

 muscle 



Ramus of man- 

 dible 



Hyo-pharyngeus 

 muscle 



Isthmus faucium 



Tonsil 



Digastricus (in- 

 termed, tendon) 



Anterior end of 

 mandibular gland 



Sublingual vein 



External maxil- 

 lary vein 



Parotid duet 



Lymph gland 



Tig. 348. — Cross-section of Head of Horse. 

 The section passes through the anterior part of the temporo-mandibular articulation, but is slightly oblique, passing 

 a few millimeters further forward on left side than on right. 1, Corpus callosum; 2, lateral ventricle of brain; S 

 caudate nucleus; 4, internal capsule; 5, lenticular nucleus; (?, optic chiasma; 7, middle cerebral artery; 5, sphenoidal 

 sinuses; .9, cavernous sinus; 10, Eustachian tube, medial lamina; 11, 11, guttural pouches; 12, soft palate; 13, epi- 

 glottis; ^4, hyo-epiglottic muscle; i-5, thyro-hyoid muscle. The tensor palati (not marked) lies medial to the ptery- 

 goideus lateralis, and medial to the tensor is the levator palati, which blends above with the outer lamina of the Eustach- 

 ian tube. 



tubse auditivEe) are situated on the lateral wall behind the posterior nares and below 

 the level of the ventral nasal meatus. They are slit-like openings, directed ob- 

 liquely downward and backward, and are a httle more than an inch (ca. 3 cm.) 

 in length. They are bounded medially by a fold which encloses the expanded 

 extremity of the cartilaginous Eustachian tube. The isthmus faucixun is the oral 

 open'ng; it is closed by the soft palate except during swallowing. The aditus 



