80 THE BONES. 



48, 2), and Wormian fronto-nasal (Fig. 48, 1), as well as an interaasal, orbital, 

 zygomato-maxillary, maxillo-nasal-incisive bone. (Sometimes two Wormian 

 bones are found in the same head.) 



OP THE HEAD IN GENERAL. 



1. Geneeal Configueation. 



From the union of all the bones which constitute the cranium and faoe, 

 there results a quadrangular pyramid, with summit inverted, which it is necessary 



to study as a whole. We will pass in 

 ^'S- *^" review, successively, its four faces, its 



base, and its summit. 



A. Anterior Face.— This is 

 subdivided into four regions (Fig. 

 49) : 



1. Parietal region. — This has for 

 base the anterior portion of the 

 occipital bone and the parietal bones. 

 Limited, above, by the external occi- 

 pital tuberosity, it presents on the 

 middle line a spur which soon bifur- 

 cates to form the parietal or temporal 

 crests ; the latter join the posterior 

 border of the zygomatic process. i 



2. Frontal region. — Larger than^ 

 the preceding, it is usually plane and 

 lozenge-shaped. Boimded iuferiorly 

 by the fronto-nasal suture, this region 

 projects, laterally, the orbital pro- 

 cesses, the base of which is pierced 

 by the supra-orbital foramen, and the 

 anterior border — somewhat sharp— 

 is frequently made irregular by small 



notches, one of which is often converted into a foramen. 



3. Nasal region. — This region has for its base the proper bones of the nose. 

 It is narrow, convex on each side, and plane, concave, or convex in its length, 

 according to the animals. It advances above the entrance to the nasal cavities, 

 where it forms the nasal prolofigation, the summit of which, in the Horse, ceases 

 at nearly two fingers' breadth from the intermaxillary symphysis. 



4. Incisive region. — Principally formed by the incisive bones, this region 

 presents : the inferior opening of the nasal cavities, divided in the fresh state by 

 the median cartilaginous septum of the nose ; the incisive slits on the floor of 

 the nasal fossfe ; the intermaxillary symphysis, channeled above by a more or 

 less deep groove in nearly all Horses, but raised, on the contrary, into a conical 

 tubercle in the Ass and Hinny, and perforated in the middle by the incisive canal. 

 Right and left of the intermaxillary symphysis this region is convex, and elevated 

 by the prominence which the roots of the incisor teeth form. 



B. Posterior Pace. — In this are recognized four distinct regions (Fig. 50) : 

 1. Sub-occipital region. — This presents : in the middle, the basilar process^ 



WORMIAN BONES OF THE OX. (AFTER CORNEVIN.) 



1, Fronto-nasal Wormian bones; 2, 2, lachrymo- 

 nasal fontanellar bones. 



