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Bruise

life science Maturity 11-13 Next article →

A bruise, scientifically known as a contusion, is a specific type of hematoma. A hematoma is a collection of blood that has pooled inside your body's tissues.

Blåmärken
Blåmärken

Most bruises are caused by blunt trauma. This occurs when physical compression or deceleration forces damage the body. These forces break tiny blood vessels called capillaries. When these vessels break, blood leaks into the surrounding interstitial tissues. This is called extravasation, which means the blood moves into the spaces between cells. Because the skin remains intact, the bleeding is localized under the surface. If the skin actually breaks, the injury is classified as a hemorrhage rather than a bruise.

When a bruise forms, your body immediately begins a complex biological response. The damaged capillary endothelium, which is the inner lining of the vessel, releases a hormone called endothelin. This hormone causes the blood vessel to narrow to minimize further bleeding. As the endothelium is destroyed, a substance called von Willebrand factor is exposed. This factor initiates coagulation, which is the process of forming a blood clot. This clot acts as a temporary plug to seal the damaged vessel.

US Army Vet Injury
US Army Vet Injury

Nerve endings in the area may detect the increased pressure from the leaking blood. This pressure is often perceived by the person as pain or physical pressure.

Medical professionals use specific terms to categorize different types of skin discoloration based on size. Small spots called petechiae are less than 3 millimetres in diameter. These can result from many causes, such as straining, asphyxiation, or reactions to medications like warfarin. Larger marks between 3 and 10 millimetres are called purpura.

severebruise
severebruise

When a mark is 1 centimetre or larger, it is called an ecchymosis. While some use the terms bruise and ecchymosis interchangeably, some schemas differentiate them. An ecchymosis may be remote from the original site of trauma. For example, "raccoon eyes," or periorbital ecchymosis, can result from a basilar skull fracture or a neuroblastoma.

The changing colors of a bruise are a visual map of how your body breaks down blood. This process involves the sequential degradation of hemoglobin, which is the protein in red blood cells. Initially, the bruise may appear red, blue, or almost black. This color depends on whether broken venules or arterioles caused the leak.

Black Eye 01
Black Eye 01

As the body processes the blood, hemoglobin breaks down into biliverdin, which creates a green color. Next, it turns into bilirubin, which appears yellow. Finally, the process results in hemosiderin, which looks golden-brown.

Black Eye 01
Black Eye 01

These products are eventually cleared by the immune system, and the bruise disappears.

Several biological factors influence how easily or severely a person bruises. Age is a major factor, as elderly skin is often thinner and less elastic. Gender also plays a role, as females may experience more bruising due to increased subcutaneous fat. Even genetics can be a factor; for instance, natural redheads may bruise more visibly.

Sprained foot
Sprained foot

The location of the injury matters as well, because areas with more extensive vascularity, like the arms and shins, tend to bleed more. Additionally, the type of tissue affects the spread. In soft tissues, blood can invade more easily, resulting in a larger bruised area than in firmer tissues.

While many bruises are minor, some can be life-threatening and are measured using a harm score from 0 to 5. A score of 0 represents a light bruise with no damage, while a score of 5 is a critical bruise that carries a risk of death.

severebruise
severebruise

Serious bruising can lead to a hematoma that forms a hard, fluctuating lump. This swelling can cause compartment syndrome, where pressure cuts off blood flow to the tissues. Severe impacts to the head can cause traumatic brain injury, involving brain swelling and bleeding. In such cases, emergency surgery might be required to relieve the pressure on the brain.

Understanding the context of a bruise is vital for medical diagnosis. For instance, bruising around the navel combined with severe abdominal pain may suggest acute pancreatitis. Unexplained bruising can also be a warning sign for various medical conditions, including leukemia, meningococcal infection, or clotting disorders.

Blaues und rotes Auge nach Fußtritt ins Gesicht (Ausschnitt)
Blaues und rotes Auge nach Fußtritt ins Gesicht (Ausschnitt)

In forensic science, bruises found during an autopsy can indicate if an injury occurred while a person was still alive. By studying these patterns, doctors and scientists can better understand the underlying cause of the injury.

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File:Blåmärken.jpg
Blåmärken.jpg
File:severebruise.jpg
severebruise.jpg
File:Sprained foot.jpg
Sprained foot.jpg
File:Blaues und rotes Auge nach Fußtritt ins Gesicht (Ausschnitt).jpg
Blaues und rotes Auge nach Fußtritt ins...
File:US Army Vet Injury.JPG
US Army Vet Injury.JPG
File:Black Eye 01.jpg
Black Eye 01.jpg
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