Hanging (Signs Of) (World of Forensic Science)
Hanging is a form of strangulation where a noose is pulled tight around the neck by the person's own body weight. The noose compresses the airways, cutting off the supply of oxygen to the lungs. It also compresses the carotid arteries, which carry blood to the brain. Both mechanisms cause asphyxia, in which body and brain are deprived of oxygen. However, asphyxia is not always the cause of death in hanging. In some cases, the pressure on the neck causes vagal inhibition, a reflex that leads to cardiac arrest. The forensic pathologist has to try to distinguish between hanging and other forms of strangulation and between suicidal, homicidal, and accidental hangings.
Most adult hangings are suicides. In children, hanging may occur by accident if they get themselves tangled up in clothes or a harness. Homicidal hanging is very rare and the generally the victim needs to be unconscious or intoxicated for such an act to occur. The ligature, that is, the material used to make the noose and suspend the victim, usually consists of whatever is at hand. Ropes, belts, and electric flex are among the most common ligatures in hangings. Clothing, washing lines, and even dog leads are sometimes used. The victim may use a fixed knot or a slip knot, the latter being particularly efficient at compressing the airways and blood vessels because it tightens so quickly under gravity.
Some hangings take place from a high point of suspension, where the body swings freely under gravity with the feet off the ground. However, hanging can also occur with the person kneeling, sitting, or half lying, from a relatively low point of suspension such as a doorknob or bedpost. The weight of the chest and arms is enough to provide fatal pressure on the neck; suspension of the whole body is not necessary. A tree is the most common suspension point in hangings occurring out of doors, but bridges or climbing frames have also been used. Indoors, there is a large range of suspension points including doors, banisters, rafters, and loft hatches, or practically any raised object. The circumstances of the hanging influence the signs on the body and the actual cause of death.
Suicide by hanging in prison is a particular problem. Obvious ligatures such as ropes or flex are clearly not made available. However, desperate people will fashion ropes out of bedclothes or their own clothes. Two of Britain's most notorious killers took their own lives by hanging in prison. Fred West hanged himself with a ligature made of strips of clothing in 1995, seemingly to avoid trial. In 2004, the serial killer Dr. Harold Shipman used bedclothes to hang himself from the window bars of his cell in Wakefield Prison.
An autopsy of a hanged body will often reveal neck markings. The nature of these depends on the type of noose. Few or no marks may be found with a noose made of a soft material like bed sheets. A rope or cord noose will, however, leave a deep furrow, often with accompanying abrasions and contusions. Hanging from a high suspension point leaves diagonal marks on the neck like an inverted V, which do not run around the full circumference of the neck. The point where the noose meets the vertical part of the rope is pulled up and away from the body and does not leave a mark on the neck. This can be used to distinguish a hanging from a manual strangulation. However, in a hanging from a low suspension point, the marks on the neck tend to be horizontal rather than diagonal and may look more characteristic of a manual strangulation.
High hangings are more likely to cause death by vagal inhibition, owing to the sudden pressure on the neck. The victim tends to be pale in such cases. A low hanging is more likely to lead to asphyxia and there may be some facial congestion and a purple protruding tongue. Asphyxia in hanging is usually related to the compression of the carotid arteries, rather than blockage of the airways. Petechial hemorrhages, caused by blood leaking from capillaries in the eyes owing to the pressure on the neck, are typical of many strangulations, but not often found in a hanging. Their absence can therefore help distinguish a hanging from other strangulations. The body may also show lividity due to pooling of blood in the legs, forearms, and hands.
In judicial execution by hanging, the body usually drops several feet, which causes disruption of the cervical vertebrae, which are the spinal bones in the neck. The cause of death, if the execution if correctly carried out, is disruption of the spine rather than asphyxia. Fractures of the cervical vertebrae are not often seen in suicidal, homicidal, or accidental hangings, unless the body has dropped through some distance.
In cases of suspected hanging, the pathologist will also carry out a toxicological analysis of the body. Drugs or alcohol sometimes play a role in hanging. It is not an easy form of homicide and a perpetrator may try to "knock out" or subdue the victim before applying the noose. In cases of suicide, the victim may drug himself or herself in an attempt to summon up the courage to carry out the act.
SEE ALSO Asphyxiation (signs of); Knots and ligatures.