(HealthDay News) -- A bruise creates a darkened area of skin, when an injury causes small blood vessels to leak below the skin's surface.

The ADAM Encyclopedia suggests how to help prevent bruises:

• Reduce your risk of falling at home by taking precautions including practicing ladder safety and being sure not to kneel or stand on high surfaces, such as a countertop.
• Always use a safety belt while you're in a vehicle.
• When playing sports, wear appropriate protective gear, such as a helmet, shoulder pads, elbow pads, shin guards, knee and thigh pads.