What is Bone Marrow ?Bone marrow is a spongy tissue found inside bones. The bone marrow in the breast bone, skull, hips, ribs and spine contains stem cells that produce the body's blood cells. This is where the blood cells (RBC’s, platelets and WBC’s) are produced where they develop. These blood cells include white blood cells (leukocytes), which fight infection; red blood cells (erythrocytes), which carry oxygen, to and remove waste products from organs and tissues; and platelets, which enable the blood to clot. Each of these carries a life maintaining function. The bone marrow is a vital part of the human body.