PATHOLOGY

Detailed explanation-1: -Black-and-blue marks reveal sites where blood has escaped from circulation and has clotted in tissue spaces; such clotted blood masses are called hematomas.

Detailed explanation-2: -Ecchymosis (ehk-ih-MO-sis) is when multiple blood vessels very close together burst, resulting in pooled blood just under your skin’s surface. Ecchymosis looks like a bruise, but it’s not always related to an injury.

Detailed explanation-3: -A bruise occurs when small blood vessels break and leak their contents into the soft tissue beneath the skin. A bruise occurs when a force causes blood vessels to break. Blood leaks into areas under the skin, resulting in pain, swelling, and skin discoloration.

Detailed explanation-4: -It often starts red because fresh, oxygen-rich blood has newly pooled underneath the skin. After around 1–2 days, the blood begins to lose oxygen and change color. A bruise that is a few days old will often appear blue, purple, or even black. In about 5–10 days, it turns a yellow or green color.