What is the X in X-mas?
"between the thighs," or in madicine, "between leg-like structures," 1690s, from inter- + Latin crus "shin, shinbone leg; supports of a bridge."
crural cru·ral (krur'əl)adj.
Of or relating to the leg, shank, or thigh.
Of or relating to a body part that resembles a leg.