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 jomt, 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 
Intercondyloid fossa 
Fic. 93.—Proxmat Extremity oF Ricur Femur oF Fie. 94.—Distat Extremity or Ricur Femur or 
Horse; Enp View. Horse; Enp View. 
1, Head; 2, fovea capitis; 3, neck; 4, 5, anterior and 1, 1’, Medial and lateral ridges of trochlea; 2, 2’, 
posterior parts of trochanter major. medial and lateral condyles; 3, 3’, medial and lateral 
epicondyles; 4, extensor fossa; 5, depression for origin 
of popliteus. 
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 tibie), 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 (Facies medialis) 
is broad above, where it presents rough prominences for the attachment of the 
