Home Up Biology Chemistry Games Lab Skills


Blood Spatter Notes


Angle of impact the acute angle formed between the direction of a blood drop and the plane of the surface it strikes.



SIN < = Width  (a) 1.5cm

              Length (c) 3.0cm

Width  (a) 1.5cm = SIN <

Length (c) 3.0cm

0.5 = SIN <

< = 30 degrees


Arterial spurting blood stain patterns resulting from blood exiting the body under pressure from a breached artery

Back spatter blood directed back toward the source of force that caused the spatter

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 determined by its angle of impact and directionality angle

Directionality the direction the blood was traveling when it hit the target surface (this can be determined by the geometric shape of the blood stain)

Directionality angle the angle between the long axis of a bloodstain and a predetermined line that represents 0 degrees

Draw-back effect blood in the barrel of a firearm that has been drawn back into the muzzle

Drip pattern a blood stain pattern that results from blood dripping into blood






Expirated blood blood that is blown out of a wound by air (usually the nose or mouth)

Flight path the path of the blood drop as it moves through space

Flow pattern a change in the shape and/or direction of a bloodstain due to the influence of gravity or movement of the target

Forward spatter blood that travels in the same direction as the source of force that caused the spatter


High-velocity impact spatter a bloodstain pattern caused by a high-speed impact or force to a blood source (usually a gunshot)

Impact pattern bloodstain pattern created when blood receives a blow or force resulting in the random dispersion of smaller drips of blood

Impact site the point where force meets a blood source

Low-velocity impact spatter a blood stain pattern caused by a low-speed impact to a blood source (drip)

Medium-velocity impact spatter a blood stain pattern caused by a medium-speed impact (beating or stabbing)


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 pattern

Passive drop (bleeding) bloodstain drops created or formed by gravity alone

Point (area) of convergence the common point on a two dimensional surface, where the directionality of several blood drops can be retraced

Point (area) of origin the common point in 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 (such as arterial spurting)

Satellite spatter small droplets of blood distributed around a drop or pool of blood hitting the target surface

Spatter blood that has been dispersed as a result of force applied to its surface

Spine the pointed or elongate stains that radiate from the central area of a blood stain

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 the surface may be visible 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.