[Origin of bone cells (author's transl)].

Is has now been well established that osteoclasts are issued from haematopoietic stem-cells and are close relatives of monocytes. However, osteoblasts come from the medullary stroma and are part of the fibroblastic lineage. The precise physiological mechanisms of bone resorption and formation are still unknown, but the numerous experimental studies on this subject recently had an unexpected therapeutic application: human osteopetrosis can be cured by grafts of haematopoietic bone-marrow.