BPA Definitions Flashcards
Accompanying Drop
A small blood drop produced as a by-product of drop formation.
Altered Stain
A bloodstain with characteristics that indicate a physical change has occurred.
Angle of Impact
The angle (alpha), relative to the plane of a target, at which a blood drop strikes the target.
Angle of Convergance
The space in two dimensions to which the directionalities of spatter stains can be retraced to determine the location of the spatter producing event.
Area of Origin
The space in three dimensions to which the trajectories of spatter can be utilized to determine the location of the spatter producing event.
Backspatter Pattern
A bloodstain pattern resulting from blood drops which can be produced when a projectile creates an entrance wound.
Blood Clot
A gelatinous mass formed by a complex mechanism involving red blood cells, fibrinogen, platelets, and other clotting factors.
Bloodstain
A deposit of blood on a surface
Bloodstain Pattern
A grouping or distribution of bloodstains that indicates through regular or repetitive form, order, or arrangement the manner in which the pattern was deposited.
Bubble Ring
An outline within a bloodstain resulting from air in the blood.
Cast-off Pattern
Bloodstain patter resulting from blood drops released from an object due to its motion.
Cessation Pattern
Bloodstain resulting from blood drops released from an object due to its abrupt deceleration.
Directionatlity
Characteristic of a bloodstain that indicates the direction blood was moving at the time of deposition.
Directional Angle
The angle (gamma) between the long axis of a spatter stain and a defined reference line on the target.
Drip pattern
Bloodstain pattern resulting from a liquid that dripped into another liquid, at least one of which was blood.
Drip stain
Bloodstain resulting form a falling drop that formed due to gravity.
Drip trail
Bloodstain patter resulting from the movement of a source of drip stains between two points.
Edge characteristic
Physical feature of the periphery of a bloodstain.
Expiration pattern
Bloodstain pattern resulting from blood forced by airflow out of the nose, mouth, or a wound.
Flow
Bloodstain resulting form the movement of a volume of blood on a surface due to gravity or movement of the target.
Forward spatter pattern
Bloodstain pattern resulting from blood drops which can be produced when a projectile creates an exit wound.
Impact pattern
Bloodstain pattern resulting from an object striking liquid blood.
Insect stain
Bloodstain resulting from insect activity.
Parent stain
Bloodstain from which a satellite stain(s) originated.
Perimeter stain
Altered stain consisting of its edge characteristics, the central area having been partially or entirely removed.
Pool
Bloodstain resulting from an accumulation of liquid blood on a surface.
Projected pattern
Bloodstain pattern resulting from the ejection of blood under hydraulic pressure, typically from a breach in the circulatory system.
Satellite stain
Smaller bloodstain that originated during the formation of the parent stain as a result of blood impacting a surface.
Saturation stain
Bloodstain resulting from the accumulation of liquid blood in a n absorbent material.
Serum stain
The stain resulting from the liquid portion of blood (serum) that separates during coagulation.
Spatter stain
Bloodstain resulting from an airborne blood drop created when external force is applied to liquid blod.
Splash pattern
Bloodstain pattern created from a large volume of liquid blood falling onto a surface
Swipe
Bloodstain resulting from the transfer of blood from a blood-bearing surface onto another surface, with characteristics that indicate relative motion between the two surfaces.
Target
A surface onto which blood has been deposited.
Transfer stain
Bloodstain resulting from contact between a blood-bearing surface and another surface.
Void
An absence of blood in an otherwise continuous bloodstain or bloodstain pattern.
Wipe
An altered stain resulting from an object moving through a pre-existing wet bloodstain.
Formula for determining area of origin
(W/L) Sine-1 = (Impact Angle) x Tan = (X) x Dist from area of convergence to leading edge of bloodstain = Area of Origin
Formula for determining angle of impact
(W/L) Sine-1 = Angle of Impact
