78 



THE BONES. 



HEAD OF THE CAT. 



1, Parieto-occipital suture; 2, parietal bone; 

 3, frontal bone ; 4, orbital process of the 

 frontal bone ; 5, malar bone ; 6, supermaxil- 

 lary bone ; 7, 7, premaxilla ; 8, nasal bone ; 

 9, tympanic bulb ; 10, inferior maxilla. 



in its curved portion ; the interdental space is very long ; and the body has only two alveoli 

 for the incisors. 



11.— The Hyoid Bone (Fig. 47). 



The hi/oid bone constitutes a small and special bony apparatus which serves 



to support the tongue, as well as the 

 Fig- ■*^- larynx and pharynx ; its description is 



placed immediately after that of the 

 bones of the head because of its con- 

 nection with that region, it being situ- 

 ated between the two branches of the 

 supermaxillary bone, and suspended from 

 the base of the cranium in an oblique 

 direction from above to below, and from 

 before to behind. 



This apparatus is composed of seven 

 distinct pieces, arranged in three series : 

 a middle, constituted by a single bone, 

 and named the bod?/ ; two lateral, form- 

 ing two quasi-parallel branches, to the 

 extremities of which the body is articu- 

 lated. 



Body or basihyal. — The body of the 

 hyoid resembles a fork with two prongs. It presents : 1. A middle part flattened 

 above and below, and consequently provided with a superior and an inferior face. 



2. A single and long pro- 

 ^'^' ^^" longation flattened on 



both sides, which is de- 

 tached from the middle 

 part, and directed forward 

 and downward to plunge 

 into the muscular tissue 

 of the tongue : this is the 

 anterior a/Ypendu of the 

 hyoideal body, or lingual 

 proJongation. 3. Two late- 

 ral corniia, thyroid cornua, 

 grpat rornaa, or arnhyah, 

 projecting backwards and 

 upwards, articulating by 

 their extremities with the 

 thyroid cartilage of the 

 larynx, and offering, at 

 their point of union with 

 the middle part, two con- 

 vex diarthrodial facets 

 looking upwards, and 

 corresponding with the styloid cornua. The body of the hyoid bone is developed 

 by three centres of ossification — a middle, and two lateral for the cornua. 



Branches. — The three pieces composing these are articulated end to end, by 



HYOID BONE OF THE HORSE. 



1, Body or ba^ihyal ; 2, lingual prolongation ; 3. 3, thvroid 

 cornua, great cornua, or urohyals ; 4, 4, styloid coriu.a, 

 small cornua, or apohyals ; 5, 5, styloid nuclei or ceratohyals ; 

 6, 6, styloids, great hyoideal branches, or stylohyals ; 7, 7, 

 arthrohyals, or cartilaginous nuclei attaching the hyoid to 

 the temporal bone. 



