Forensic Serology: Blood Spatter 

Determining the Area of Origin of a Bloodstain

 

 One of the most important tasks that a forensic serologist must undertake, is finding where the blood came from in a three dimensional plane. In order to accomplish this, the serologist must determine the area of convergence.

The area of convergence can be  found by drawing lines through the center of the blood droplets to determine directionality. Upon analyzing multiple droplets, the area of convergence will be revealed on a 2D axis.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                                           

                                                               

 

 

 

 

After determining where the bloodstain orginated from on a 2D axis, the forensic serologist must find the area of origin which will translate the area of convergence into a third dimensioal area by adding height to the equation. In order to find the height, the angle of impact (sinΘ) must be calculated. SinΘ can be found by dividing the width of the blood droplet by the length (W/L)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

After determining the angle of impact, string can be attached to the droplets of the bloodstain, and fixing the string so that it mimics the angle of impact, this will raise the area of convergence into the third dimension, turning it into the area of origin.