In this con­text, blood-forming stem cells or blood stem cells. They are cells with litt­le or no dif­fe­ren­tia­ti­on. The various blood cells deve­lop from the­se parent cells. The­se stem cells are usual­ly found in the bone mar­row, espe­cial­ly of the iliac crest, the ster­num (bre­ast­bo­ne), and thigh bone.