holy bone in english, paralleling german heiliges bein or heiligenbein (alongside kreuzbein) and dutch heiligbeen. the origin of galen's term is unclear. supposedly the sacrum was the part of an animal offered in sacrifice (since the sacrum is the seat of the organs of procreation). others attribute the adjective ἱερόν to the ancient belief that this specific bone would be indestructible. as the greek adjective ἱερός may also mean "strong", it has also been suggested that os sacrum is a mistranslation of a term intended to mean "the strong bone". this is supported by the alternative greek name μέγας σπόνδυλος by the greeks, translating to "large vertebra", translated into latin as vertebra magna. in classical greek the bone was known as κλόνις (latinized clonis); this term is cognate to latin clunis "buttock", sanskrit śróṇis "haunch" and lithuanian šlaunis "hip, thigh". the latin word is found in the alternative latin name of the sacrum, ossa clunium, as it were "bones of the buttocks". due to the fact that the os sacrum is broad and thick at its upper end, the sacrum is alternatively called os latum, "broad bone". additional images image of a female pelvis seen anteriorly, sacrum at centre. lateral surfaces of sacrum and coccyx. base of sacrum. median sagittal section of the sacrum. left levator ani from within. the posterior divisions of the sacral nerves. sacrum. pelvic surface. sacrum. dorsal surface.