Classification of Sequesterum:

According to shape :
Pencil – Infants
Cylindrical/tubular – Infants
Ring – External fixator
Conical – Amputation stump
Annular – Amputation stump
Coralliform – Perthes’ disease

According to consistency :
Coke like – Tuberculosis
Feathery – Syphilis
Sand like – TB osteomyelitis in metaphysis

According to Color :
Black – Amputation stump , Fungal osteomyelitis
Green – Pseudomonal Osteomyelitis