Bone mar­row is found insi­de the lar­ge bones, espe­cial­ly in the iliac crest, sternum
(bre­ast­bo­ne), and ribs. The bone mar­row can rege­ne­ra­te its­elf, con­ti­nuous­ly pro­du­cing blood
cells and immu­ne cells. Sin­ce most of the­se cells have a life span of only a few days to several
weeks, the func­tion of the bone mar­row is cri­ti­cal to survival.