Large Volumes of Blood:

The following patterns were created by the same volume of blood and distance from the source to the target surface.

 

Blood Dripping into Blood

 

 

Splashed (Spilled) Blood

 

 

Projected Blood (with a syringe)

 

 


Blood Spatter Patterns:

Blood spatter patterns are created when an exposed blood source is subjected to an action or force greater than gravity (internally or externally).

The size, shape and number of resultant bloodstains will depend generally on the amount of force applied to the liquid blood.

Impact Patterns

 

 

Cast-off Patterns

 

 

Projected Pattern (Arterial)

 

 


Directionality of Bloodstains:

When a droplet (spherical) impacts a surface at a perpendicular angle (90 degrees) the resulting bloodstain will appear circular i.e. the length a width of the stain are equal.

When a blood droplet impacts a surface at an angle less that 90 degrees, the resulting bloodstain with have an elongated or elliptical appearance.  In addition, the tail of the droplet will indicate the direction of travel of the droplet when it contacted the surface i.e the opposite direction from where the droplet originated from.

            


Angle of Impact Determination:

The angle of impact can be mathematically determined based on the elliptical appearance of a spherical blood spatter stain.

 

 

 

SIN< = width / length

< = invsin (width / length)

e.g. < = invsin(1.5 / 3.0)

< = invsin(0.5)

< = 30 degrees

Therefore, the droplet originated from a source that was approximately
30 degrees 'out' from the plane of the target surface.

 


.....continued on page 3