Hanging Injuries and Strangulation 

With its relatively small diameter, lack of bony shielding, and close association of the airway, spinal cord, and major vessels, the human neck is uniquely vulnerable to life-threatening injuries. Throughout recorded history, various methods of strangulation (ie, disruption of normal blood and air passage in the neck) have been used by both assailants and penal systems to produce injury and death.

Hanging is a form of strangulation that involves suspension by the neck. Hangings can be classified as either complete or incomplete. When the whole body hangs off the ground and the entire weight of the victim is suspended at the neck, the hanging is said to be complete. Incomplete hangings imply that some part of the body is touching the ground and that the weight of the victim is not fully supported by the neck. Hangings may also be classified by intent (eg, homicidal, suicidal, autoerotic, accidental).

Significant cervical spinal cord and bony injuries are most common in hangings that involve a fall from a distance greater than the height of the victim. The prognosis in such injuries is dismal.

The pathophysiology of morbidity and mortality from strangulation injuries is controversial, save for the case of judicial hangings. In a judicial hanging, the drop is at least as long as the height of the victim and the hanging is complete. The mechanism of death is effectively decapitation, with distraction of the head from the neck and torso, fracture of the upper cervical spine (typically traumatic spondylolysis of C2 in the classic hangman fracture), and transection of the spinal cord. Direct spinal cord injury may or may not be the cause of death in suicidal hangings.

In other mechanisms of strangulation injuries, whether by manual choking, application of tool or ligature, or postural asphyxiation (eg, children whose necks are caught in an object such as a crib, a hanging towel loop, or a window cord), pathophysiologic theories to account for observed outcome include the following:

• Venous obstruction, leading to cerebral stagnation, hypoxia, and unconsciousness, which, in turn, produces loss of muscle tone and final arterial and airway obstruction
• Arterial spasm due to carotid pressure, leading to low cerebral blood flow and collapse
• Vagal collapse, caused by pressure to the carotid sinuses and increased parasympathetic tone

Interestingly, none of the proposed mechanisms treats airway compromise as the immediate cause of collapse. In fact, although mechanical airway compromise occurs and ultimately complicates patient management, it appears to play a minimal role in the immediate death of victims of successful strangulation. Many jujitsu and aikido strangles (eg, hadaka-jime and variants) are applied to the vascular structures of the neck and not the trachea. Several reports exist of suicidal posttracheostomy patients who successfully hung themselves with ligatures well above the tracheostomy, where death did not appear to be related to spinal cord injury.

Most experts agree that regardless of the events occurring in any given hanging or strangulation, death ultimately occurs from cerebral hypoxia and ischemic neuronal death.

Frequency

United States

In 2005, the National Center for Injury Prevention and Control reported 13,920 deaths nationwide from "suffocation", for an age-adjusted rate of 4.63 per 100,000. This includes "other accidental hanging and strangulation (category) W76", "accidental suffocation and strangulation in bed, W75", "hanging, strangulation, and suffocation, Y20", and the portmanteau category "other accidental threats to breathing, W75-W84".^[1]

Strangling injuries are common, as the necessary weapons are as close as the attacker's own hands. An estimated 5-10% of urban assaults involve strangulations or ligature assaults.

International

Judicial hangings are uncommon worldwide. However, accidental hanging and strangulation injuries are becoming more prevalent in urban centers.^{[2, 3]} Causes include an increased prevalence of the "choking game" and autoerotic "breath play" (see Causes).

Mortality/Morbidity

• If death is not immediate, the risk of delayed airway obstruction is significant.
• Tracheal intubation can be difficult if laryngeal edema is present or if direct traumatic disruption of the larynx has occurred.
• Strangulation injuries account for approximately 2.5% of all traumatic deaths worldwide.

Race

• No clear racial trends have been identified in victims of hanging and strangulation.

Sex

• Women are victims of strangulation assault more frequently than men.
• In contrast, nearly all reported autoerotic strangulation deaths involve men.
• Suicidal hangings were once considered to be far more common among men. Recent trends suggest that women are increasingly likely to use hanging than other common methods of suicide (firearms and poisoning).

Age

Several populations are at risk of hanging or strangulation.

• Toddlers in postural asphyxiation: Ill-constructed cribs allow toddlers to be caught by the neck and strangled as they put their heads out. Window cords have also been implicated in such deaths.
• Adolescents: Suicidal depression can lead to hanging. There appears to be an increasing incidence of accidental hanging and strangulation due to "the choking game", a practice involving voluntary near-strangulation in order to enjoy the altered mental state and physical sensations.
• Young adults: Autoerotic accidents, assault, and suicidal depression are common causes. Prison inmates often choose hanging if suicidal; it is one of the few methods available to them.