Related for Nazir 7:6

There is no difference between an olive-sized piece of a corpse and an entire corpse except that the [tumah associated with the] piece of a corpse [exits through] an opening the size of a handbreadth, whereas the [tumah associated with the] entire corpse [exits through] an opening the size of four handbreadths. There is no difference between a olive-sized piece of a corpse and a piece of a bone larger than a barley seed except for the propensity to contaminate other things in a closed space [which a bone does not have]. There is no difference between a limb taken from a corpse and a limb taken from a living person except that flesh from a limb taken from a corpse is tamei and flesh from a limb taken from a live person is tahor.