40 THE EXTERIOR OF THE HORSE 



posing cause of roaring. This affection does not have its seat in the 

 nasal fossae. Narrowness of the face is an absolute defect. 



2. Lateral Regions. The lateral divisions present but little of 

 importance. We will observe, nevertheless, that they do not present 

 altogether the same conformation at different periods of the animal's 

 life. Thus, they are more prominent in young horses, because the 

 molar teeth are more deeply implanted into the alveoli of the superior 

 maxilla ; as age advances and the teeth are continually worn, the latter 

 are pushed from their sockets, and these regions appear more concave. 



Diseases and Blemishes. The blemishes of the face are : 



1. Deformities consequent to fracture of the nasal bones from traumatisms 

 received by the parietes of this region. These fractures are rare, not only because 

 the bones themselves possess a marked degree of resistance, but also because the 

 elasticity of the air contained in the nasal fossae to a great extent breaks the 

 momentum of blows received upon their surface. Nevertheless there is danger 

 of producing, either by the displacement of the bones or the consequent forma- 

 tion of a callus, a serious obstacle to the free passage of the air during ordi- 

 nary respiration and particularly during exercise. Other deformities may exist 

 upon the lateral parietes of the face. These are tumefactions which result from a 

 chronic lesion of the mucous membrane of the maxillary sinuses, due to necrosis 

 of a tooth or other alterations of a diverse nature, whose gravity varies with the 

 cause. 



2. Traces of Cauterization. At the present time cauterization of the face 

 is seldom practised. The Arabs employed it in the treatment of strangles and 

 benign affections of the superior respiratory passages. With these exceptions, 

 such blemishes indicate that the animal has been or is still suffering from a 

 grave disease of the nasal cavities. 



3. Cicatrices which are the result of traumatisms, excoriations, or thicken- 

 ings of the skin caused by the halter or bridle ; finally, cicatrices of an angular 

 or semicircular shape, arousing the suspicion that the maxillary sinuses have 

 been trephined. These last are situated within the maxillary spine towards the 

 internal angle of the eye. 



When any of the blemishes enumerated are present, it is necessary to com- 

 plete our examination by a minute inspection of the nasal sinuses, the molar 

 teeth, and the subrnaxillary lymphatic ganglia. 



C. Extremity of the Nose (Fig. 19.) 



Situation ; Limits ; Anatomical Base. The extremity of 

 the nose is situated at the inferior extremity of the face, between the 

 nostrils and above the superior lip. 



Anatomically it comprises for its base the anterior extremity of the septum 

 nasi and the comma-shaped cartilages which encircle the internal alse of the 

 nostrils. The external face of the latter is covered by the transversalis nasi 

 muscle, which is separated on the median line from the fine integument of this 

 region by the terminal tension of th maxillo-labialia muscle. 



