14 MANUAL FOR STABLE SERGEANTS. 



(a) The bones of the cranium inclose the brain, and, together with 

 the bones of the face, form the orbital and nasal cavities, in which are 

 situated the organs of sight and smell. 



(b) The bones of the face form the skeleton of the mouth and nasal 

 cavities, and support the tongue and larynx. The most important 

 bones of this region are the maxillae (upper jaw) and the mandible 

 (lower jaw), each of which, on either side, presents six irregular 

 cavities for the reception of the cheek (molar) teeth. From the 

 orbital cavities forward the upper jaw gradually becomes narrower 

 and terminates in the premaxilla, which contains the six upper 

 incisor teeth; these six, with the corresponding teeth of the lower 

 jaw, help form the anterior boundary of the mouth. 



(c) In each maxilla, just below the orbit, is an inclosed irregular- 

 shaped cavity known as the maxillary sinus. It connects with the 

 nasal cavity and contains the roots of the last three cheek teeth. 



5. The teeth are 40 in number, and are of three kinds, viz: 



(a) The incisors, 12 in number, are situated in the front ;part of the 

 mouth, 6 in the premaxilla and 6 in the anterior extremity of the 

 lower jaw. 



(b) The canines (tushes), 4 in number, are situated in the inter- 

 dental space just back of the incisors. In the mare these teeth are 

 usually very small or wanting entirely. 



(c) The cheek teeth (molars), are 24 in number, and are situated in 

 the back part of the mouth, 6 above and 6 below on each side of each 

 jaw. The space between the incisors and molars is called the inter- 

 dental space. 



6. The spinal or vertebral column may be regarded as the basis 

 of the skeleton from which all other parts originate. It extends from 

 the base of the skull to the tip of the tail, and consists of a chain of 

 irregular bones called vertebrae, all solidly united by ligaments and 

 cartilage. According to their position in the column, they are di- 

 vided into five regions, which are, naming them from front to rear, 

 the cervical, thoracic, lumbar, sacral, and coccygeal. 



(a) In the cervical region there are 7 bones, which form the frame- 

 work of the neck, the first being called the atlas and the second the 

 axis, the remaining 5 having no special names. 



(b) The thoracic vertebrae are 18 in number. They furnish attach- 

 ment for the upper ends of the ribs, and their superior spines, from 

 the second to the eighth, inclusive, form the framework of the 

 "withers. 



