The region at the end of a long bone between the joint surface and the neck of the shaft (metaphysis).The epiphysis consists of a dense network of bony trabeculae (spongy bone) between which lies red bone marrow. Surrounded the spongy bone is a layer of compact bone, the area of bone that forms the joint surface is covered by a layer of hyaline cartilage and the bone directly underneath it is known as sub-chondral bone.