Strangulation may be defined as an act of violence in which constriction is applied directly to the neck, either around it or in the forepart, in such a way as to destroy life. This definition obviously includes hanging, which differs from other forms of strangulation only in that the body is suspended. The direct cause of death in the great majority of cases is arrest of the respiration owing to pressure on the windpipe—i.e. asphyxia. If much violence is used, it may be produced by direct injury to the upper part of the spinal cord from fracture or dislocation of the cervical vertebrae (as is now the rule in execution by hanging), or by syncope from shock, and in such cases must be almost instantaneous. On the other hand, if the constriction is so applied as to compress the great vessels in the neck and not the windpipe, as may happen in 'garotting,' it is due to coma, and is somewhat slower than in cases of asphyxia. Or if both vessels and windpipe are compressed, coma and asphyxia may both contribute to cause death.
The internal appearances of the body after death are those of Asphyxia (q.v.), with specially marked congestion of the brain; the most constant external appearances are congestion of the face, with prominence of the eyes and protrusion of the tongue, and marks on the neck corresponding to the cord or other constricting agent. The latter are most evident and the injuries to the neck most severe in homicidal cases. Death by hanging (excepting judicial executions) is almost always suicidal; by other forms of strangulation it also is frequently suicidal, but often homicidal. Accidental strangulation in any form is rare.
When suspension of the body has not continued for much more than five minutes, and the parts about the neck have not suffered violence, there is a probability that resuscitation may be established; although many cases are recorded when after only a few minutes' suspension it has been found impossible to restore life. Moreover, if a person who has hanged himself has been cut down sufficiently soon to allow of the respiratory process being restored, he is by no means safe: death often taking place from secondary effects at various periods after the accident. It is believed that unconsciousness comes on very rapidly, and death takes place without causing any suffering; the violent convulsions that are so often observed being similar to those which occur in epilepsy. In homicidal cases, however, the appearance of the face sometimes indicates much distress. A man named Hornshaw, who was on three occasions resuscitated from hanging—a feat which he performed in London for the amusement of the public—stated that he lost his senses almost at once; and other persons who have been restored state that the only symptoms of which they were conscious were a ringing in the ears, a flash of light before the eyes, then darkness and oblivion. The treatment to be adopted after the patient has been cut down may be briefly summed up as follows: Exposure to a free current of air, cold affusion if the skin is warm, the application of ammonia to the nostrils, of mustard poultices to the chest and legs, and of hot water to the feet, and the subsequent abstraction of blood if there should be much cerebral congestion; above all, artificial respiration should be used if natural breathing do not at once commence. From the post-mortem appearances, together with circumstantial evidence, the medical practitioner is not unfrequently called upon to decide such questions as these: Was death caused by hanging, or was the body suspended after death? Was the strangulation the result of accident, homicide, or suicide? In case of strangulation from other causes than that of hanging the post-mortem symptoms are similar, but the injury done to the parts about the neck is commonly greater. In manual strangulation the external marks of injury will be in front of the neck, about and below the larynx; and if death has been caused by a ligature the mark round the neck will be circular, whereas in hanging it is usually oblique. The internal appearances are much the same as in the case of hanging. See Taylor's or other text-book of Medical Jurisprudence.