Decapitation is the total separation of the head from the body. Such an injury is invariably fatal to humans and most other animals, since it deprives the brain of oxygenated blood by way of severing through the jugular vein and common carotid artery, while all other organs are deprived of the involuntary functions that are needed for the body to function.
The term beheading refers to the act of deliberately decapitating a person, either as a means of murder or as an execution; it may be performed with an axe, sword, or knife, or by mechanical means such as a guillotine. An executioner who carries out executions by beheading is sometimes called a headsman.[1] Accidental decapitation can be the result of an explosion,[2] a car or industrial accident, improperly administered execution by hanging or other violent injury. The national laws of Saudi Arabia and Yemen[3] permit beheading. Under Sharia, which exclusively applies to Muslims, beheading is also a legal punishment in Zamfara State, Nigeria.[4] In practice, Saudi Arabia is the only country that continues to behead its offenders regularly as a punishment for capital crimes. Cases of decapitation by suicidal hanging,[5]suicide by train decapitation[6][7] and by guillotine[8] are known.
Less commonly, decapitation can also refer to the removal of the head from a body that is already dead. This might be done to take the head as a trophy, as a secondary stage of an execution by hanging, for public display, to make the deceased more difficult to identify, for cryonics, or for other, more esoteric reasons.[9][10]