<Tr> <Th> FMA </Th> <Td> 9608 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> Bone marrow is a semi-solid tissue which may be found within the spongy or cancellous portions of bones . In birds and mammals, bone marrow is the primary site of new blood cell production or hematopoiesis . It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells . On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately 2.6 kilograms (5.7 lb). Human marrow produces approximately 500 billion blood cells per day, which join the systemic circulation via permeable vasculature sinusoids within the medullary cavity . All types of hematopoietic cells, including both myeloid and lymphoid lineages, are created in bone marrow; however, lymphoid cells must migrate to other lymphoid organs (e.g. thymus) in order to complete maturation . </P> <P> Bone marrow transplants can be conducted to treat severe diseases of the bone marrow, including certain forms of cancer such as leukemia . Additionally, bone marrow stem cells have been successfully transformed into functional neural cells, and can also potentially be used to treat illnesses such as inflammatory bowel disease . </P>

Where is the bone marrow found in a long bone