An occipital bun, also called an occipital spur, occipital knob, chignon hook or inion hook, is a prominent bulge or projection of the occipital bone at the back of the skull. It is important in scientific descriptions of classic Neanderthal crania.[1] It is found among archaic Homo species (including Neanderthals), as well as Upper Pleistocene Homo sapiens and present-day human populations.[2]