L2.2 Bloodstain Patterns and Analysis

Vocabulary Term

Notes

Example

Bloodstain Pattern Analysis

• The study and interpretation of bloodstains

• Analyzes patterns, shapes, sizes, and distribution of blood spatters

• Provides insight of how and where bloodshed occurred

Antigens

Outside substances that can be recognized by antibodies

Antibodies

Triggers an immune response from leukocytes

Blood Spatter

Small droplets and dispersed (often due to strong force)

Blood Splatter/Splash

Big volume of blood and concentrated (usually only gravity)

Drips

Bloodstains formed by the force of gravity acting on blood; creating droplets with well-defined shape (usually circular)

Flows

Bloodstains created by the movement of a volume of blood on a surface due to gravity

Swipe

Bloostains caused by object (rough/uneven) coming into contact with a surface and moving across it

Wipe

Resulting from object (smooth) moving through an existing wet bloodstain - appearance is wiping motion

Contact Patterns

Occur when a wet or bloody surface comes into contact with a second surface

Spatter

Resulting from forceful projection of blood and mst pattern often due to a high velocity impact or force

Cast-off

Bloodstains created when a blood covered object flings blood onto surfaces while in motion. Pattern often shows series of arced or linear stains  

Arterial Spurt

Bloodstains resulting from blood exiting an artery under pressure. Pattern is characterized by projecting, high-velocity streams of blood 

Expirated Blood

Blodstains caused by blood forced by airflow out of the nose, mouth, or  wound. Appear as fine mist-like droplets (sometimes bubbling)

Void

Absence of bloodstains in a specific area due to an object/person blocking bloods trajectory

Satellites

Small blood stains surrounding a central bloodstain due to the ejection of blood droplets upon impact

Spines

Elongated patterns from a central bloodstain; resulting from blood droplets contacting a non-smooth surface 

Velocity

High velocity force → blood stains that are most-like/dispersed

Low velocity force → bigger droplets and less dispersed

Surface

Nonporous and smooth surface →smooth edges and round circle

Porous and rough surface → uneven edges and irregular shape

Angle of Impact

Angles in which blood droplets reached the surface can affect the shape of bloodstains; smaller the angle, more elongated shape is

Viscosity

Blood is thicker → allows it resist change in flow better

Temperature

High temp → blood less viscous coagulate faster, and evaporates faster

Lower temp → blood more viscous, coagulate slower, and evaporates slower