The hangman's knot or hangman's noose (also known as a collar during the Elizabethan era) is a well-known knot most often associated with its use in hanging a person. For a hanging, the knot of the rope is typically placed under or just behind the left ear, although the most effective position is just ahead of the ear, beneath the angle of the left lower jaw. The pull on the knot at the end of the drop levers the jaw and head violently up and to the right, which combines with the jerk of the rope becoming taut to wrench the upper neck vertebrae apart. This produces very rapid death, whereas the traditional position beneath the ear was intended to result in the mass of the knot crushing closed (occluding) the neck arteries, causing cessation of brain circulation. The knot is non-jamming but