Determining Angles of Impact
As mentioned earlier, a blood droplet in freefall has the shape of an oscillating sphere. Should the droplet strike a surface and a well-formed stain is produced, an analyst can determine the angle at which this droplet struck the surface. This is based on the relationship between the length of the major axis, minor axis, and the angle of impact.
A well-formed stain is in the shape of an ellipse (see figure 1). Dr. Victor Balthazard, and later Dr. Herbert Leon MacDonell, realized that the width-length ratio of the ellipse is the sine of the impact angle. Accurate measurement of the stain thus allows easy calculation of the impact angle.
Read more about this topic: Bloodstain Pattern Analysis
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