48 THE 
costarum). 
SKELETON OF THE HORSE 
Except in the case of the first, the cartilage does not continue the 
direction of the rib, but forms with the latter an angle which is open in front, and 
increases from second to last. 
More or less extensive ossification is to be regarded 
as a normal occurrence, especially in the cartilages of the sternal ribs. 
THE STERNUM 
The sternum of the horse is shaped somewhat like a canoe; it is compressed 
laterally, except in its posterior part, which is flattened dorso-ventrally. 
* 
~-----Cariniform 
, cartilage 
f 
Ventral 
border 
Costal 
cartilages~~~. 
- Ribs 
-) 
' 
NXiphoid cartilage 
Fig. 25.—Sternum anp CostaL CARTILAGES OF 
Horse; VentrAL View. (After Ellenberger- 
Baum, Anat, f. Kinstler.) 
It is 
inclined obliquely so that the posterior end 
is about six to eight inches (15 to 20 em.) 
lower than the anterior. 
The dorsal surface (Facies dorsalis) has 
the form of a very narrow isosceles triangle 
with the apex in front. It is concave longi- 
tudinally, flattened transversely. 
The lateral surfaces (Facies laterales) 
are convex above, slightly concave below, and 
diminish in extent behind. Each presents on 
its upper part seven costal cavities (Fovewe 
costales), with which the sternal ends of the 
second to the eighth costal cartilages inclu- 
sive articulate. These cavities are situated 
in series at the intersternebral junctions. 
The first four are elliptical in outline with 
the long diameter vertical, and are sepa- 
rated by considerable regular intervals. 
The others are progressively smaller, more 
circular, and closer together. The area 
below these cavities gives attachment to the pectoral muscles. 
The dorso-lateral borders separate the dorsal and lateral surfaces. 
They give 
attachment to the lateral branches of the sternal ligament. 
The ventral border forms the prominent keel-like crest of the sternum (Crista 
sterni) which may be felt in the living animal; it fades out behind. 
Tic. 26.—SternuM or Horse; Laterau View. 
The sternebre are designated by Roman numerals and the costal facets by ordinary figures. 
The anterior extremity or manubrium sterni! can be distinctly felt in the 
central furrow of the breast. It consists largely of a laterally compressed cartil- 
aginous prolongation, commonly called the cariniform cartilage. Its lateral sur- 
faces are flat and furnish attachment to muscles of the breast and neck. The 
'The manubrium sterni of man is equivalent, strictly speaking, to the cariniform cartilage 
+ the first osseous segment of the horse. 
