Passive bloodstains Passive bloodstains are those stains created by the force of gravity. Passive Drop – Bloodstain drop(s) created or formed by the force of gravity acting alone. Drip Pattern – A bloodstain pattern which results from blood dripping into blood. Flow Pattern – A change in the shape and direction of a bloodstain due to the influence of gravity or movement of the object. Pool Pattern – A bloodstain pattern formed when a source of blood is stationary for a period of time.
Projected bloodstains A projected stain occurs when some form of energy has been transferred to a blood source. Low Velocity Impact Spatter (LVIS) – A bloodstain pattern that is caused by a low velocity impact\force to a blood source. Medium Velocity Impact Spatter (MVIS) – A bloodstain pattern caused by a medium velocity impact\force to a blood source. A beating typically causes this type of spatter. High Velocity Impact Spatter (HVIS) – A bloodstain pattern caused by a high velocity impact\force to a blood source such as that produced by gunshot or high-speed machinery. Cast-Off Pattern – A bloodstain pattern created when blood is released or thrown from a blood-bearing object in motion. Arterial Spurting (OR Gushing) Pattern – Bloodstain pattern(s) resulting from blood exiting the body under pressure from a breached artery. Back Spatter – Blood directed back towards the source of energy or force that caused the spatter. Expiratory Blood – Blood that is blown out of the nose, mouth, or a wound as a result of air pressure and/or air flow which is the propelling force.
