Judicial hanging in earlier centuries was the result of strangulation. Death in most suicidal hanging is also caused by strangulation, through compression of the jugular veins in the neck and probably the carotid arteries, even sometimes the airways, so that suffocation as well as interference with the cerebral circulation may also be a factor. Death from strangulation is inevitably comparatively slow.

Conversely, judicial hanging by the use of the drop from a suddenly opened trapdoor, on which the criminal is standing, is usually fast. These deaths occur because of the disarticulation (separation) of the neck vertebrae that results in the breaking of the spinal cord. The joints are also displaced sideways — provided that the knot has been placed under the angle of the jaw so that a sideways pressure is exerted on the neck as the subject falls.

The speed of death is dependent on there being a long enough drop to ensure separation of the neck joint and sufficient sideways force to make certain that the cord is severed. The skill of a hangman is in assessing the correct drop for the weight and build of the prisoner, so that the cord is severed but the prisoner is not decapitated. Too short a drop, or one without sideways pressure, may result in strangulation; too long a drop in decapitation. The more pronounced the angle of the jaw, the more likely that the knot will exert the necessary pressure on the neck to make death all but instantaneous.

Reports suggest that Saddam died as quickly as is possible in a judicial hanging. How long the brain remains oxygenated once the cord has been severed is debated. General opinion is that if it is well carried out, as in the case of Saddam, consciousness is lost within seconds and all brain activity has ceased within a minute or two.

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