medulla ossium
[TA] bone marrow: the soft material filling the cavities of the bones, made up of a meshwork of connective tissue containing branching fibers, the meshes being filled with marrow cells, which consist variously of fat cells, large nucleated cells or myelocytes, and giant cells called megakaryocytes. See also m. ossium flava and m. ossium rubra.
Medical dictionary.
2011.