176 



THE ANATOMY OF THE HORSE. 



distributed mainly to the gland of the same name, but it sends some 

 twigs to the upper eyelid. 



The Orbital Branch of the Superior Dental Artery creeps over the 

 lower part of the rim of the orbit, and descends to anastomose with the 

 submaxillary artery. It gives some twigs to the lower eyelid. 



Nerves. The sensory nerves of the eyelids are derived from the 

 supra-orbital and palpebro-nasal branches of the ophthalmic division of 

 the 5th cranial nerve, and from the orbital branch of the superior 

 maxillary division of the 5th. The supra-orbital nerve emerges by the 

 foramen of the same name, and is distributed to the upper eyelid, and to 

 skin around its point of exit. The palpebro-nasal nerve sends a branch 

 to supply the lower lid and the structures at the inner canthus. 

 The orbital branch of the superior maxillary division of the 5th nerve 

 is distributed in the neighbourhood of the outer canthus. The motor 

 nerve to the orbicularis comes from the 7th, which crosses internal to 

 the nasal canthus. The motor nerve to the levator palpebree comes 

 ft'om the 3rd, but cannot be reached at present. 



THE FACE. 



The Nostrils, or the Inferior or Anterior Naees. Some points in 

 connection with these may conveniently be noticed before the student 



proceeds to dissect the 

 face. The nostril is the 



entrance to the nasal 



chamber or fossa — the first 

 segment of the respiratory 

 passages. It is a large, 

 somewhat oval opening 

 bounded laterally by the 

 alee, ox wings, of the nostril. 

 The alse meet above and 

 below, forming the com- 

 missiires, the lower of 

 which is wide and rounded, 

 while the upper is acute. 

 The outer ala is concave -in 

 the whole of its extent ; 

 but the inner ala, while 

 concave below, forms a 



1,1. comma-like cartilages of the nostril; 2. Septal cartilage. COnvex projection cloSe tO 



the upper commissure. If 

 now the inner wing be manipulated, it will be felt to contain a piece 

 of cartilage which begins above in the convex projection close to the 

 upper commissure, extends downwards and round the infeiior commis- 



Fl6. 20. 



