\Crus\ (kr?s), n.; pl. {Crura} (kr?"r?). [L., the leg.]
(Anat.)
(a) That part of the hind limb between the femur, or thigh,
    and the ankle, or tarsus; the shank.
(b) Often applied, especially in the plural, to parts which
    are supposed to resemble a pair of legs; as, the crura of
    the diaphragm, a pair of muscles attached to it; crura
    cerebri, two bundles of nerve fibers in the base of the
    brain, connecting the medulla and the forebrain.