The distal extremity is large in both directions and comprises the _trochlea_ in front and two _condyles_ behind, one internal and one external. The condyles are separated by the _intercondyloid fossa_, or _fossa intercondyloidea_, which is marked with pits for the attachment of ligaments; and above this is the _epitrochlear fossa_. [Illustration: FIG. 12.—Bones of the hind extremity. _A._ Posterior view of femur. _B._ Anterior view. 1, Shaft. 2, Proximal extremity. 3, Distal extremity. 4, Articular head. 5, Trochanter major. 6, Shallow trochanteric fossa. 7, Convexity over which the tendon of the gluteus maximus glides. 8, External condyle. 9, Internal condyle. 10, Nutrient foramen. 11, Intercondyloid fossa. 12, Muscular linear ridges. 13, Epitrochlear fossa. _C._ Internal view of tibia. _D._ External view. 1, Shaft. 2, Articular head. 3, Distal end. 4, The rotular process. 5, The fibular ridge. 6, External condyle. 7, Internal condyle. 8, Intercondyloid space. 9, Nutrient foramen. _E._ Fibula, lateral view. 1, Articular head. 2, Its attenuated portion. _F._ Posterior view of metatarsus. 1, Trochlea for inner or second digit. 2, Trochlea for middle or third toe. 3, Trochlea for outer digit. 4, Bony core for spur. 5, Bony canal for tendons. 6, Groove for tendons. 7, Fossa intercondyloidea. ] The _inner condyle_ begins anteriorly as a ridge, and expands into a convexity which attains its greatest breadth posteriorly where it becomes more flattened. The inner side of the inner condyle is flattened and is provided with a tuberosity at its mid-part and a second just above the posterior part of the condyle. The _outer condyle_ is formed in the same manner as the inner condyle. It is indented at its broad, lower end by an _angular groove_, which, winding divides the posterior part of the condyle into two convexities. The more external convex ridge and the groove dividing it from the outer condyle are adapted to the head of the fibula. There is in this part a _fibular ridge_ and above this ridge a tuberosity. =The Tibia.= _Location._—The tibia (Fig. 12, _D_ and _C_) extends obliquely downward and backward from the knee-joint to the hock. It articulates above with the femur and, by its procnemial process with the patella, below with the metatarsus, and laterally with the fibula. _Description._—The tibia is the longest bone in the posterior limb, and possesses a shaft and two extremities. It is largest at the proximal end and presents three faces.