distal portions are attached to the
tibial tarsal (astragalus), fibular tarsal (calcaneum) bone, fourth
tarsal (cuboid) and metatarsus bones.

[Illustration: Fig. 44--Left stifle joint; medial view. The capsules are
removed. (From Sisson's "Anatomy of the Domestic Animals.")]

The plantar ligament (calcaneo-cuboid) is a strong flat band which is
attached to the plantar surface of the fibular and fourth tarsal bones
(calcaneum and cuboid) and the head of the lateral metatarsal (external
small) bone.

The dorsal (oblique) ligament is attached above to the distal tuberosity
on the inner side of the tibia. It is inserted below to the central
(cuneiform magnum) and third (c. medium) tarsal bones, to the proximal
ends of the large and outer small metatarsal bones.

The tarsus is a true hinge joint and because of the great strain which
it sustains, is subject to frequent injury. About seventy-five percent
of cases of lameness affecting the hind leg may be said to arise from
disease of the hock.

As members of locomotion the legs receive strains of two kinds: those of
concussion and weight-bearing and strains of propulsion; the latter are
the greater. In the horse as a work animal, the hind legs are probably
subjected to greater strains than are the front but the manner of
construction of the various parts of the pelvic limbs with the possible
exception (according to some authorities) of the tibial tarsal joint,
offsets this condition.

The femur may be considered analagous to the humerus in that it bears a
similar relationship to the ilium, that exist between the humerus and
scapula. Further flexion during repose is prevented chiefly by the
glutens medius (maximus) muscle and its tendons. The larger tendon
inserts to the summit of the trochanter major of the femur and
corresponds to the biceps brachii in the action of the latter on the
scapulohumeral joint, except that the gluteus medius, in attaching to
the femoral trochanter, exerts its effect as a lever of the first class.
Because of the relationship between the long axes of the femur and iliac
shaft it is evident that the angle formed by these two bones is
maintained chiefly by the gluteus muscles during weight bearing.
Contraction of muscular fibers of the gluteus medius causes extension of
the femur and muscular strain is prevented to a great degree by the
inelastic portion of this muscle. The chief physiological antagonistics
of the glutei are the quadriceps fem