MUSCLES OF THE METATARSUS AND DIGIT 343 
Blood-supply.—Posterior tibial artery. 
Nerve-supply.—Tibial nerve. 
5. Popliteus (Fig. 298).—This thick, triangular muscle lies on the posterior 
surface of the tibia above the popliteal line. 
Origin.—A small depression on the lateral epicondyle of the femur, close to 
the articular surface and under the lateral ligament. 
Insertion —A triangular area on the posterior surface of the tibia, proximal and 
medial to the popliteal line; also the proximal half of the medial border and a 
narrow adjacent part of the medial surface of the tibia. 
Action.—To flex the femoro-tibial joint and to rotate the leg inward. 
Structure —The strong tendon of origin lies at first under the lateral ligament, 
end curves backward and inward over the lateral condyle of the tibia in contact 
with the lateral meniscus; it is invested by a reflection of the synovial membrane 
of the joint (Fig. 584). The tendon is succeeded by a thick triangular belly, the 
fibers of which are directed medially in the proximal part, but incline downward 
below. 
Relations——Superficially, the fascia and skin, semitendinosus, gastrocnemius, 
superficial flexor; deeply, the femoro-tibial joint, the tibia, the popliteal vessels 
and their divisions. The saphenous vessels and nerve lie along the medial border 
of the muscle, separated from it, however, by the deep fascia. 
Blood-supply.—Popliteal and posterior tibial arteries. 
Nerve-supply.—Tibial nerve. 
MUSCLES OF THE METATARSUS AND DIGIT 
Extensor digitalis brevis —This small muscle lies in the angle of union of the 
tendons of the long and lateral extensors of the digit. (Fig. 293.) 
Origin.—The lateral tendon of the peroneus tertius, the middle annular liga- 
ment, and the lateral ligament of the hock. 
Insertion —The tendon of the long extensor. 
Action —To assist the long extensor. 
Structure —It is principally fleshy, having a superficial origin from the annular 
ligament, and a deep one (by a thin tendon) from the lateral tendon of the peroneus 
tertius. The insertion is by a thin tendon. 
Relations—Superficially, the skin and fascia and the tendons of the long and 
lateral extensors; deeply, the tarsal joint capsule, the great metatarsal artery, and 
the deep peroneal nerve. 
Blood-supply.—Great metatarsal artery. 
Nerve-supply.—Deep peroneal nerve. 
The interossei and lumbricales are arranged like those of the thoracic limb, 
the only noticeable difference being the greater development of the lumbricales in 
the pelvic limb. 
THE MUSCLES OF THE OX 
MUSCLES OF THE FACE 
The cutaneus is much more developed than in the horse, presenting as a special 
feature the extensive frontalis muscle, which covers the frontal and nasal regions. 
The orbicularis oris does not form a complete ring, the defect being in the 
middle of the upper lip. 
The levator nasolabialis is extensive, thin, and not very distinct from the 
