Strangulation

Strangulation causes injury through several overlapping mechanisms. The most rapid effect is occlusion of the carotid arteries and jugular veins, which reduces cerebral blood flow and leads to unconsciousness within seconds. Airway obstruction (tracheal compression) is a slower process, but can be significant in ligature or manual strangulation. Pressure on the carotid sinus can trigger a reflex bradycardia or cardiac arrest, sometimes without significant visible injury.

Forensic pathologists classify strangulation into three main types: manual (by hands), ligature (using a cord, belt, or similar), and hanging (where the body weight is suspended by a ligature). Hanging is typically suicidal, while manual strangulation is almost always homicidal. Ligature strangulation can be either homicidal or accidental, and rarely suicidal.

External signs of strangulation include petechiae (small hemorrhages) on the face, conjunctivae, and skin above the ligature, as well as abrasions, bruises, and fingernail marks. However, the absence of external marks does not exclude strangulation, especially in manual cases where the assailant's grip may leave minimal trace. Internal findings may include fractures of the hyoid bone or thyroid cartilage, which are more common in manual strangulation than in hanging.

Investigators must distinguish strangulation from other causes of asphyxia, such as smothering or choking. The presence of a ligature mark, its position, and the pattern of petechiae help determine the mechanism. In living victims, forensic nurses and physicians document injuries using photography and standardized checklists, as these cases often proceed to prosecution.

Non-fatal strangulation is now recognized as a sentinel act in intimate partner violence, with studies showing that victims who have been strangled are at significantly higher risk of later homicide. Many jurisdictions have enacted specific criminal statutes for strangulation, distinct from general assault, reflecting its severity. Survivors may suffer from delayed neurological symptoms, including stroke, due to carotid artery dissection, and psychological trauma such as PTSD.

Medical evaluation of survivors should include imaging (CT or MRI) to rule out vascular injury, and careful documentation for legal purposes. The term 'choking' is often misused by the public to mean strangulation, but medically choking refers to an internal airway obstruction, not external neck compression.

Autoerotic asphyxia, a form of accidental strangulation during solitary sexual activity, is a rare but well-documented phenomenon, often involving ligatures designed to release when consciousness is lost. In historical contexts, 'garroting' was a method of robbery and execution, and the Spanish garrote was a legal execution device until the 20th century. In forensic entomology, the presence of petechiae can be masked by decomposition, complicating postmortem diagnosis.

Strangulation has also been used in martial arts and law enforcement as a 'sleeper hold' or 'chokehold', which can cause unconsciousness without permanent injury if released promptly, but carries inherent risks. The term 'strangulation' is sometimes used metaphorically in economics, such as 'strangulation of trade', but this article focuses on the physical act.

Asphyxia

A condition of severe oxygen deficiency in the body, often due to inability to breathe normally.

Petechiae

Small red or purple spots caused by bleeding under the skin, often seen in strangulation.

Hyoid bone

A U-shaped bone in the neck that supports the tongue; its fracture is a classic sign of manual strangulation.

Ligature

A cord, belt, or other material used to constrict the neck.

Carotid sinus

A dilated area of the carotid artery that contains baroreceptors; pressure here can cause a reflex drop in heart rate.