a) Ball: Ball & socket is a type of joint in which the end of one bone consists a ball like structure which fits into another bone which has a socket like structure. Hip joint and knee joint are the types of ball & socket joint.

b) Periosteum: Periosteum consists of dense irregular connective tissue which forms the outer layer of the bone. It serves as protection layer for the bone and serves as a channel for the blood supply and nutrients for bone tissue.

c) Yellow marrow: Yellow bone marrow produces fat, cartilage and bone. White blood cells develop here.

d) Compact bone: Compact bones are dense bones in which the bone is solidly filled with organic groung substance and inorganic salts, leaving only small spaces which have blood cells in them.