Coccyx

The coccyx is a vestigial feature that shows the common ancestry of mankind and apes.

He hit his coccyx in a fall.

The coccyx is the vestigial structure of a tail.

The coccyx is a vestigial trait.

He lands on the concrete path and bounces on his coccyx, which cracks the base of his spine.

An actor herself, McAlpine was hands-on, demonstrating “how you penetrate” on screen: “If you can move your coccyx, just arch your back slightly, it looks fantastic,” she says happily. “Those orgy scenes were amazing.”