THE SKELETON OF THE HORSE 



Ventral 



border 



Costal "' 

 cartilages"~--.^ 



Cariniform 

 cartilage 



Ribs 



costarum). 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. It is 



inclined obliquely so that the posterior end 

 is about six to eight inches (15 to 20 cm.) 

 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 (Foveae 

 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. 



Xiphoid cartilage 



Fig. 2.5. — Sternum and Cost.^l Cartilages of 

 Horse; \'enthal View. (After Ellenberger- 

 Baum, Anat. f. Kiinstler.) 



VH-^VI 





Fig. 26. — Sternum of Horse; Lateral View. 

 The sternebrEe 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 



1 The manubrium sterni of man is equivalent, strictly speaking, to the cariniform cartilage 

 -f the first osseous segment of the horse. 



