The term Necrosis is equivalent to local death of tissue, and includes all forms of lesions in which any portion of the body loses its vitality. Gangrene has a more limited significance, being applied chiefly to cases in which the necrosis is accompanied by putrid decomposition of the part, and especially to death of considerable portions of the external parts of the body. Mortification has a similar meaning. Sloughing is the death and separation by ulceration of smaller parts of the soft external tissues. Sphacelus has a similar significance. Necrosis is sometimes used in the limited sense of death of bone or cartilage.