=Extensor pedis brevis= (M. extensor digitalis brevis).—This small
muscle lies in the angle of union of the long and lateral extensors of
the digit. (Shown in Fig. 201, but not marked.)
_Origin._—The outer tendon of the peroneus tertius, the middle annular
ligament, and the outer lateral ligament of the hock.
_Insertion._—The tendon of the anterior or long extensor.
_Action._—To assist the anterior or 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 outer
tendon of the peroneus tertius. The insertion is by a thin tendon.
_Relations._—Superficially, the skin and fascia and the tendons of the
anterior and lateral extensors; deeply, the 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.