<Tr> <Th> FMA </Th> <Td> 83698 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> The medullary cavity (medulla, innermost part) is the central cavity of bone shafts where red bone marrow and / or yellow bone marrow (adipose tissue) is stored; hence, the medullary cavity is also known as the marrow cavity . Located in the main shaft of a long bone (diaphysis) (consisting mostly of compact bone), the medullary cavity has walls composed of spongy bone (cancellous bone) and is lined with a thin, vascular membrane (endosteum). However, the medullary cavity is the area inside any bone (long, flat, etc .) that holds the bone marrow . </P> <P> This area is involved in the formation of red blood cells and white blood cells, and the calcium supply for bird eggshells . </P>

Where do the medullary cavities of bone exist