BLOODSTAIN PATTERN ANALYSIS Flashcards
What is blood pattern analysis
-ACTIVITY AT SCENE
-NUMBER OF BLOWS
-POSITION OF VICTIM
-WEAPN CHARACTERISTICS
THE USE OF BIOLOGY, PHYSICS AND MATHEMATICS TO INTERPRET BLOODSTAIN PATTERNS
WHAT IS BLOOD MADE UP OF
BLOOD IS MADE UP OF FLUID PLASMA AND CELLS (RIGID SHAPE)
NEWTONIAN
ZERO SHEAR RATE
ZERO SHEAR STRESS
VISCOSITY: CONSTANT
WATER AND AIR
NON NEWTONIAN FLUIDS
VARIABLE RELATIONSHIP WITH SHEAR STRESS
VISCOSITY: VARIABLE
BLOOD AND TOOTHPASTE
VISCOSITY
MEASURE OF FLUID RESISTANCE TO FLOW
SHEAR STRESS
A FORCE causing deformation of a material by slippage
along a plane or planes parallel to the imposed stress
BASIC PRINCIPLES
a free falling drop of blood forms a sphere or ball
LOW VELOCITY SPATTER
5ft/second and usually 3 mm or greater in diameter indicates blood is dripping
MEDIUM VELOCITY SPATTER
5-25 ft/second with a diameter of 3 mm and usually
indicates blunt trauma, sharp, trauma and cast-off
HIGH VELOCITY SPATTER
100ft second with a spatter of 1 mm in diameter indicating gunshot trauma, power tools, and object striking with extreme velocity
what is the role of plasma
to transport nutrients and hormones
what is the definition of a bloodstain pattern
a grouping of bloodstains indicating deposition
why are blood stains important in violent crime reconstruction
they provide dna evidence
what is passive pattern
Bloodstains that result from gravity acting on an injured body, such as drops, flows, pools, and clots
which properties of human blood are considered when analyzing bloodstain patterns
biological and physical properties
what results in a bloodstain
liquid blood coming in contact with a surface
what are the four main components of blood
plasma, red blood cells, white blood cells, platelets
what is Bloodstain Pattern:
a grouping of bloodstains that indicates through form, order, or arrangement, the manner in which the pattern was deposited”
Bloodstain Pattern Analysis (BPA):
BPA can help reconstruct the sequence of events
BPA can corroborate or refute statements
The study focuses on analyzing bloodstains’ shapes, sizes, locations, and distribution patterns to understand the physical event that led to their occurrence.
Target surface
The physical characteristics of the surface that is coming in contact with the blood
what is drip stain
a bloodstain resulting from a falling drop
formed due to gravity
what is drip trail
a bloodstain pattern resulting from the
movement of a source of drip stains between two
points
what is drip pattern
a bloodstain pattern resulting from a
liquid dropped into another liquid, at least one of
which is blood
what is flow
a bloodstain pattern resulting from the
movement of a volume of blood
what is pool/saturation
when blood collects on a level and undisturbed
surface
when a pool of blood is absorbed through the
surface of the object
transfer patterns
A pattern created when a bloody surface comes in contact with another surface
Swipe
A pattern resulting from the transfer of blood from a bloodied surface onto
another surface
Wipe
A pattern resulting from an object moving through a pre-existing bloodstain
Impact spatter
A blood stain pattern resulting from an object striking liquid blood
Cast-off pattern
Created when blood is flung from a blood-bearing object in motion onto a
surface
SPATTER PATTERNS
External force on an open source of blood
An airborne drop of blood created by an external force
What is expected overall shape of a bloodstain that was impacted the target at a 90-degree angle
Blood falls as a sphere
