What is compact bone ?
Compact bone 
Compact bone is hard dense outer covering of bone .
In compact bone many haversian system present that is called functional units of compact bone .Haversian system – haversian system made up of central canal and 5 to 20 Lamela.
Central canal present in middle of the haversian system and contain nerve and blood vessels.
Haversian stem also called osteon.
Surround Haversian system there is 5 to 20 Lamela.
Lamellae made up of collagen and calcium phosphorus.and it is constriction ring around central canal.
Haversian system consists of lamellae and central canal
In Lamela there is many lacunae.and each lacunae contain one osteocyte
Around the lacuna there is canal system which connects with each other and connect with the central canal.and this is called canaliculi.
Through this canaliculi osteocyte get Nutrition.
Between two haversian system there is canal system called perforating canal.or volkmann canal .
SPONGY ( Cancellous, trabecular)bone
Spongy bone looks like honey comb .
Due to honey comb arrangement , there’s cavity in the bone . 7