Source:http://linkedlifedata.com/resource/umls/id/C0682560
NCI: A type of bone tissue. There are two subtypes of mature bone - compact and spongy. Compact bone is very dense and hard on the outside. Compact bone forms the thick-walled tube of the shaft of long bones and covers the epiphyses of long bones. Spongy bone is lightweight and consists of trabeculae, which branch and intersect to form a sponge like network, and red bone marrow for hematopoiesis. Short bones and the epiphyses of long bones consist mainly of spongy bone.