334 



DIGESTIVE SYSTEM OF THE HORSE 



Its tendon is then reflected around the hamulus of the pterygoid bone, being held 

 in position by a fibrous band and lubricated by a bursa. It turns inward and ex- 

 pands in the aponeurosis of the soft palate. It tenses the soft palate. 



Vessels and Nerves. — The blood-supply of the soft palate is derived from the 

 internal and external maxillary arteries. The nerves come from the trigeminus, 

 vagus, and glosso-pharyngeal nerves. 



The floor of the mouth in its anterior part is free and is formed by the body of 

 the mandible, covered by mucous membrane. The remainder is concealed by the 

 attached portion of the tongue, with the exception of a narrow space on each side 



Septutn nasi Superior Diaitits 



N aso-lacrimal duct 



Infraorbital nerve 

 and vessels 



Levator labii superi- 

 oris proprius 



Superior buccal 

 nerve 

 Facial artery 



Superior buccal 

 glands 



Parotid duct 



Labial veins 

 Lnferior labial artery 

 Mylo-hyoideus 



Superior turbinal 

 Common meatus 



Middle meatus 



Inferior turbinal 

 Inferior meatus 



'Maxillary sinus 

 {anterior end) 



f^ P (dative artery 

 Facial artery 



Buccal mucous 

 membrane 



Buccinator 



Hypoglossal 

 nerve 

 Lingual artery 



Inferior buccal nerve 

 Branches of lingual nerve 



Submaxillary duct 

 Sublingual gland 



Digastricus Suhlingual artery 



Fig. 240. — Cross-skction of Head of Horse just in Front of Faci.\l Crest. 



cavity of inferior turbinal; 3, cavuni oris; 4. 4. genio-glossi; 5, 5, genio-hyoidei; 

 ', lower fourth cheek tooth. Line to facial artery cros.ses zygomaticus. 



1, Cavity of superior turbinal; 2 

 6, hyo-glossus; 7, upper, 



of the latter. About ojiposite the canine tooth on each side is a papilla, the 

 caruncula sublingualis, through which the duct of the submaxillary gland opens. 

 Just behind these papilla? is a median fold of mucous membrane which passes to the 

 under surface of the tongue, constituting the frenum linguae. On either side are 

 the sublingual crests, which extend from the frenum to the level of the fourth 

 cheek tooth. The crest presents numerous small papilla^, through which open the 

 ducts from the subjacent sublingual gland. ^ Behind the last tooth a vertical fold 



' In the undisturbed state of the parts there is no space between the tongue and the rami 

 of the lower jaw; consequently the tongue must be drawn aside to see the sublingual crest. 



