20 
Fic. 16.—Srer- 
NUM, VENTRAL 
VIEW. 
a, manubrium; 
4, the separate 
pieces forming 
the body; ¢, bony 
part of the xi- 
phoid process 
(the expanded 
cartilaginous por- 
tion not being 
shown); d, facet 
for attachment of 
first rib. 
THE SKELETON OF THE CAT. 
Ill. STERNUM. (Fig. 16.) 
The sternum consists of three portions, a 
cranial piece or manubrium (a), a caudal piece 
or xiphoid process (c), and a middle portion or 
body (corpus), which is divided into a number 
of segments (4). 
To the sternum are united the ventral ends 
of the first nine ribs. It thus forms the median. 
ventral boundary of the thorax. Since the 
thorax decreases in dorsoventral measurement 
craniad, the long axis of the sternum is inclined 
from its caudal end dorsocraniad, and if con- 
tinued would strike the vertebral column in the 
region of the first cervical vertebra. 
The manubrium (a) makes up about one-fifth 
the whole length of the sternum and projects 
craniad of the first rib. It has the form of a 
dagger and presents a dorsal surface and two 
lateral surfaces, the latter uniting ventrad to 
form asharpangle. In the middle of the lateral 
surface near the dorsal margin is an oval articu- 
lar surface (¢@) borne on a triangular projection. 
It looks caudodorsad and is for the first costal 
cartilage. 
The caudal end articulates with the body by 
a synchondrosis and presents a slightly marked 
oval facet on each side for the second costal 
cartilage. 
The body consists of six cylindrical pieces (4) 
enlarged at their ends and movably united by 
synchondroses. They increase in breadth from 
the first, and decrease slightly in length and 
thickness. At the caudal end of each near its 
ventral border there is a pair of facets looking 
caudolaterad. They are for the costal carti- 
lages. 
The xiphoid process (c) is a broad thin plate 
of cartilage at its caudal end; bony and cylin- 
