mar'row

A soft reddish or yellowish substance filling the medullary cavities and canals of bones. In the medullary cavity of the long bones it is yellow {yellow m.), and is composed of fat cells supported by retiform ti ue. In the articular ends of the long bones and in the other bones the fat cells are fewer, but numerous rounded nucleated cells are present, and smaller reddish cells like the primitive nucleated corpuscles of the embryo, which have been regarded as transition forms between m. cells and red blood corpuscles {red m.). Various preparations of m. have been used in anemia. beef m. The m. obtained from the long bones of a cow or ox; used as an article of food and as a remedy for anemia, fetal m. The ma , consisting of blood ve els, osteoblasts, and mucoid connective ti ue, which fills the primary cavities or medullary spaces of a developing endochondral bone. gelatinous m. Semitransparent, soft, gray or red m. sometimes found in healthy persons, but most frequently observed after protracted diseases, m. cavities. See primary areolae, under areola, red m. The reddish non-fatty m. contained in the articular ends of the long bones, in the flat and short bones, the vertebrae, sternum, and ribs, yellow m. The soft yellow m. filling the shafts of the long bones. It contains 96 per cent, of fat.