114 



THE SKELETON OF THE HORSE 



are separated by the deep intercondyloid fossa (Fossa intercondyloidea), and 

 articulate with the condyles of the tibia and the menisci of the stifle joint. A ridge 

 connects each condyle with the lower part of the corresponding ridge of the trochlea. 

 The intercondyloid fossa lodges the spine of the tibia and the cruciate ligaments of 

 the stifle joint, which are attached here. 



The condyles are obliquely placed with their long axes directed downward, forward, and 

 inward. The articular surface of the lateral condyle is more strongly convex from side to side 

 than that of the medial one, and the ridge which connects it with the trochlea is much narrower. 



The medial epicondyle (Epicondylus medialis) is a rounded prominence on 

 the medial surface of the distal extremity, to which the collateral ligament and the 

 adductor muscle are attached. The corresponding lateral epicondyle (Epicondylus 



Fig. 93. — Proximal Extremity of Right Femur of 



Horse; END^^'IEw. 



1, Head; 2, fovea- capitis; 3, neck; 4, 5, anterior and 



posterior parts of trochanter major. 



3'- 

 5- 



Inter condyloid Joss, i 



Fig. 94. — Distal Extremity of Right Fe-\ivr of 

 Horse; End View. 

 1, V, Medial and lateral ridges of trochlea; 2, 2\ 

 medial and lateral condyles; 3, 3', medial and lateral 

 epicondyles; 4, extensor fossa; 5, depression for origin 

 of popUteus. 



lateralis) is less distinct; it presents a mark where the lateral ligament is attached, 

 below and behind which there is a depression (Fossa musculi poplitei) in which the 

 popliteus muscle arises. Between the lateral condyle and trochlea is the extensor 

 fossa (Fossa extensoria), in which the common tendon of origin of the extensor 

 digitalis longus and peroneus tertius is attached. 



Development. — The shaft and the distal end each ossify from one center, but 

 the proximal end has two centers, one of which is for the head and the other for the 

 trochanter major. The edge of the trochanter tertius also has a separate center. 

 The proximal end fuses with the shaft at three to three and a half years, the distal 

 at about three and a half years. 



THE TIBIA 



The tibia is a long bone which extends obliquely downward and backward 

 from the stifle to the hock. It articulates above with the femur, below with the 

 tarsus, and laterally with the fibula. It possesses a shaft and two extremities. 



The shaft (Corpus tibiae), large and three-sided above, becomes smaller and 

 flattened in the sagittal direction below, but widens at the distal end. It presents 

 for notice three surfaces and three borders. The medial surface (Fades mediahs) 

 is broad above, where it presents rough prominences for the attachment of the 



