The compression of the neck by an external force is a serious event that can lead to severe injury or death. Understanding the mechanics behind this trauma is necessary for recognizing its profound and often hidden physical impact. This article explains the terminology and the complex physiological processes that occur when the neck is subjected to external compression. Any such incident requires immediate and thorough medical evaluation, regardless of the apparent severity of initial physical signs.
Defining the Terminology
The umbrella term for the external compression of the neck that interferes with normal body function is strangulation. This force can be applied by hands, a ligature, or the weight of the body. Strangulation causes a low oxygen state in the brain, which can lead to unconsciousness or fatal outcomes.
The term throttling is a specific subtype of strangulation that refers exclusively to manual strangulation, where compression is applied by human hands or fingers. This action is distinct from choking, which is the medical term for an internal obstruction of the airway, such as when food is lodged in the throat. The precise medical distinction lies in the location of the obstructive force: external for strangulation and internal for choking.
Physical Mechanisms of Injury
Strangulation causes harm through three primary physiological pathways, often acting in combination. The first mechanism involves vascular compression, which restricts blood flow to and from the brain. This compression affects the carotid arteries, reducing the supply of oxygenated blood, and the jugular veins, preventing deoxygenated blood from draining away.
The jugular veins are much easier to compress than the arteries, meaning venous return is often blocked first. This blockage leads to a rapid increase in pressure within the head, causing cerebral congestion and swelling. Loss of consciousness can occur in as little as 6 to 10 seconds following complete obstruction of blood flow to the brain.
The second mechanism is airway compression, where the trachea is obstructed, leading to asphyxia or a lack of oxygen. The trachea is relatively rigid and requires approximately six times more pressure to collapse than the blood vessels. Complete airway closure is less common in throttling than vascular occlusion, but it compounds oxygen deprivation to the brain.
A third mechanism involves nerve and reflex stimulation. The neck contains the carotid sinus, a baroreceptor located near the division of the carotid artery, and the vagus nerve. Pressure on the carotid sinus can trigger the carotid sinus reflex, causing an immediate drop in heart rate (bradycardia) and blood pressure (hypotension). This reflex action can rapidly lead to cardiac arrest and immediate collapse.
Different Methods of Compression
The force causing strangulation can be categorized based on the method of application. Manual strangulation, or throttling, involves direct force applied by a person’s hand or hands. This method often leaves characteristic fingertip or nail abrasions on the neck, though external marks may not always be visible.
A second category is ligature strangulation, where an object such as a rope, belt, cord, or wire is used to constrict the neck. This method is sometimes referred to as garrotting, and the force is applied without the body’s weight, distinguishing it from hanging. Ligature strangulation typically leaves a distinct, uniform mark around the neck that corresponds to the material used.
A third form is postural or positional compression, which occurs when the body’s position itself restricts respiration or circulation. This often happens when a person is placed or falls into a position that presses the neck or chest against an object, preventing adequate breathing or blood flow. Certain restraint techniques, like a chokehold or sleeper hold, also fall under the broader category of strangulation.
Immediate and Delayed Consequences
The consequences of throttling and other forms of strangulation range from immediate signs to severe delayed complications. Immediately following an incident, a person may exhibit petechiae, which are tiny red, purple, or brown spots caused by burst capillaries in the face, eyelids, or mouth. Other visible signs can include neck pain, hoarseness or voice changes due to laryngeal trauma, difficulty swallowing (dysphagia), and neck swelling.
Despite these potential signs, studies show that in approximately 50% of non-fatal strangulation cases, there are no immediate, visible external injuries. The lack of marks can lead to the severity of the trauma being minimized. The most significant dangers are often the delayed and hidden consequences stemming from internal damage.
Internal injuries can include subtle fractures to the larynx or the hyoid bone, a small U-shaped bone in the neck. More concerning are vascular injuries, such as a carotid artery dissection—a tear in the wall of the carotid artery. This injury can lead to the formation of a blood clot, which may travel to the brain, causing a stroke or a Transient Ischemic Attack (TIA) hours, days, or weeks after the incident. Because neurological damage is not always immediate, a person who feels fine must still seek urgent medical attention.