Medically-speaking, a bruise is called a contusion. It is a type of hematoma, which is a pooling of blood outside of a blood vessel. Most bruises involve only the surface of the skin, but they can go more deeply into the muscle and bone. Contusions are usually caused by blunt trauma, whether it is bumping into a table or being struck by another person. When the trauma occurs, it causes small blood vessels, called capillaries, to burst. When they burst, blood leaks out under the skin before the capillaries can close themselves off.
The colors of a bruise change as the hemoglobin in the blood breaks down. At first, bruises are more of a reddish color. They quickly change to purple and then blue. As time wears on, hemoglobin degrades into biliverdin and bilirubin that change the color to green and yellow, respectively.
Bruises are normally larger in softer tissues. It is more difficult for blood to spread in firm tissues. Older people also tend to bruise more than younger people. As we age, the skin loses elasticity and becomes thinner. This makes bruises more apparent.
Bruises are measured in severity on a scale of 0 to 5. A 0 on the scale is a light bruise with no associated damage. Level 1 is “less than moderate,” while level 2 is moderate with some tissue damage. Levels 3 and 4 are serious and extremely serious. Levels 3 and 4 can be dangerous. The worst bruise is a level 5. Level 5 bruises are critical and can cause death. Level 2 and higher bruises are usually accompanied with other injuries such as sprains, strains, pulled muscles, or broken bones.
The usual treatment for bruising is application of an icepack and over-the-counter painkillers. Gentle massaging can help to reduce swelling and speed up healing.
Posted 3383 day ago