GENERAL VIEW OF THE SKULL. 



37 



The Skull. 



GENERAL VIEW. 



The skull, or skeletoQ of the head, the most anterior part of 

 the horse's skeleton, articulates with the first cervical vertebra, 

 from which it is suspended by its posterior extremity, its anterior 

 extremity being free. Its position 

 varies with the attitude of the animal ; 

 but in our descriptions we shall 

 allude to it as if it were placed in a 

 horizontal position, as in Fig. 12. 



In the young animal the skull is 

 composed of a number of bones, all of 

 which, with the exception of the lower 

 jaw, the teeth, the bones of the tongue, 

 and ossicles of the ear, become united 

 by ossification in the adult ; excluding 

 tlie teeth and the internal bones of the 

 ear, there are thirty -eight bones in the 

 skull — six single ones, and the rest 

 pairs. 



The skull is divisible into two parts 

 — viz., the cranium or calvarium, and 

 the face. The former is a cavity situ- 

 ated in the supero-posterior region of 

 the skull, and continuous with the 

 spinal canal; it contains the brain and 

 its appendages, and in the horse is 

 comparatively a small cavity, occupying 

 about one-fifth of the skull. The re- 

 maining bones of the skull collectively 

 form the face, hence the whole struc- 

 ture is composed of cranial and facial 

 bones. We shall first endeavour to 

 give a general idea of the articulated 



skull, and afterwards describe separately the bones v/hich com- 

 pose it. 



The bones of the head are in early life united to each other 

 by means of sutures, or interposed layers of fibrous material, and 

 after union by ossification, a well-marked line usually indicates 



Fig. 10. 



Skull of the Horse seen from above 

 I. Occipital bone ; II. Parietal bone ; 

 III. Squamosal bone ; IV. Frontal 

 bone ; V. Nasal bone ; VI. Lachrymal 

 bone ; VII. Malar bone ; VIII. Sup- 

 erior Maxilla ; IX. Premaxilla. a. 

 Occipital crest ; b, Parietal crest ; c. 

 Orbital process ; d. Supraorbital for- 

 amen. 



