Angle of impact
The acute angle formed between the direction of a blood drop and the plan of the surface it strikes.
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 toward the source of energy or force that caused the spatter.
Blood spatter analysis
A field of forensic science that deals with the physical properties of blood and the patterns produced under different conditions as a result of various forces applied to the source of blood.
Bloodstain
Evidence that liquid blood has come into contact with a surface.
Cast-off pattern
A bloodstain pattern created when blood is released or thrown from a moving blood-bearing object.
Contact stain
Blood deposited from direct contact between two surfaces, at least one of which is bloody.
Direction of flight
The trajectory of a blood drop, which can be established by its angle of impact and directionality angle.
Directionality
The directionality of a bloodstain or pattern hat indicates the direction the blood was traveling when it hit the target surface; investigators can usually establish directionality of a blood drop's flight from the geometric shape of the bloodstain.
Directionality angle
The angle between the long axis of a bloodstain and a predetermined line on the plane of a target surface that represents 0 degrees.
Draw-back effect
Blood in the barrel of a firearm that has been drawn backward into the muzzle.
Drip pattern
A bloodstain pattern that results from blood dripping into blood.
Expirated blood
Blood that is blown out of the nose, mouth or a wound as a result of air pressure or air flow, which is the propelling force.
Flight path
The path of a blood drop as it moves through space, from the impact site to the target.
Flow pattern
A change in the shape and direction of a bloodstain due to the influence of gravity or movement of the object.
Forward spatter
Blood that travels in the same direction as the source of energy or force that caused the spatter.
High-velocity impact spatter (HVIS)
A bloodstain pattern caused by a high-speed impact or force to a blood source such as that produced by gunshot; velocity may be 100 ft/sec, generally forming drops ? 1 mm.
Impact pattern
Bloodstain pattern created when blood receives a blow or force resulting in the random dispersion of smaller drips of blood.
Impact site
That point where force meets a blood source.
Low-velocity impact spatter (LVIS)
A bloodstain pattern caused by a low-speed impact or force to a blood source; velocity may be up to about 5 ft/sec with a drop size of a 4 to 6 mm.
Medium0velocity impact spatter (MVIS)
A bloodstain pattern caused by a medium-speed impact or force to a blood source; a beating or stabbing typically causes this type of spatter, and velocity may be about 25 ft/sec with a stain generally of 1-4mm.
Misting
Blood that has been reduced to a fine spray as a result of the energy or force applied to it.
Parent drop
A drop of blood that casts off a wave or satellite spatter.
Passive drop (bleeding)
Bloodstain drop(s) created or formed by the force of gravity acting alone.
Point (area) of convergence
The common point (area), on a two-dimensional surface, over which the directionality of several blood drops can be retraced.
Point (area) of origin
The common point (area) on a three-dimensional space to which the trajectories of several blood drops can be retraced.
Projected blood pattern
A bloodstain pattern produced by blood released under pressure, as opposed to an impact, such as arterial spurting.
Satellite spatter
Small droplets of blood distributed around a drop or pool of blood as a result of the blood hitting the target surface.
Spatter
Blood that has been dispersed as a result of force applied to its source; a spatter pattern will vary depending on the force that created it.
Spine
The pointed or elongated stains that radiate from the central area of a bloodstain.
Swipe pattern
The transfer of blood from a moving source onto an unstained surface; the direction of travel may be determined by the feathered edge.
Target
The surface on which blood has been deposited.
Transfer or contact pattern
A bloodstain pattern created when a wet, bloody surface comes in contact with a second surface, a recognizable image of all or a portion of the original surface may be observed in the pattern.
Void
An absence of stains in an otherwise continuous bloodstain pattern, like a reverse shadow.
Wipe pattern
A bloodstain pattern created when an object moves through an existing stain, removing it or changing its appearance.