If the flow of arterial blood only is arrested, the part depending upon it for nutrition becomes numb, cold and shrivelled, and the form of mortification known as dry gangrene occurs.
Toes can become gangrenous and can appear black in dry gangrene or when infected becomes covered in pus and slough in wet gangrene.
Local necrosis is mainly ischaemic as thrombosis blocks the local blood vessels and causes dry gangrene.