Projected Stains
Projected stains are bloodstains that are caused when a force that is greater than gravity is used to create the bloodstain.
Arterial Spurts
Arterial spurt patterns occur when blood exits from a pressurized, breached arterial vessel, it exits as a column of blood and separates into drops as the victim moves around. This type of pattern may continue to form as long as the heart continues to beat. When the heart stops, the pressure drops and the blood is no longer forced out in a projected pattern.
Cast-Off
Cast-off patterns occur when blood is flung or projected from an object in motion, or from an object that immediately stops some motion. These stains are linear patterns that reflect the relative position of the item from which the blood was flung. They may also indicate a minimum number of strikes.
Blowback
Blowback stain patterns occur when blood is deposited inside the barrel of a firearm after the weapon has been fired.
Expirated Blood
Expirated blood patterns occur when blood is forced from the nose, mouth or respiratory system under pressure. Coughing and gasping creates a misting of the blood droplets as they exit the body and will often appear as larger blood droplets as well as a fine mist of droplets. Air bubbles can often be seen in expirated bloodstain patterns.
Impact Pattern
Impact blood patterns occur when an object strikes liquid blood and projects the blood onto a surrounding surface.