Blood spatters and stains

What is blood?

Vital complex biological fluid containing red blood cells, only found in vertebrates.

What is a bloodstain pattern?

A physical geometric image created by blood contacting a surface or vice versa.

What does bloodstain pattern analysis (BPA) involve?

Interpretation of information presented by bloodstain patterns to help reconstruct crime scenes.

What physical properties affect bloodstain patterns?

Surface tension, viscosity, internal cohesion, drop formation, fluid dynamics, specific gravity, aerodynamic behavior.

What can be inferred from bloodstains?

Direction, angle of impact, origin, applicable forces, trajectory, object ID, actor positions, sequence of events.

What are the types of bloodstain patterns?

Passive, projected, impact, impression, and artifactual patterns.

What is backsplatter?

Ejection of blood and tissue from the entrance wound of a gunshot.

How is the angle of impact determined?

By dividing the width of a bloodstain by its length and multiplying by the arcsine.

What is meant by the origin of a bloodstain?

The place from which the blood came in space, its physical location.

What is the significance of blood in reconstruction?

Identifying and locating actors and their actions to suggest scenarios and motives.

What practices are essential for preserving blood as evidence?

Photographing, measuring, using clean instruments, drying/refrigerating, and documenting patterns.

What is serology in the context of blood evidence?

Standard analysis of blood that can help in identification.

What does the mathematical relationship A² + B² = C² represent?

The Pythagorean theorem used for determining 3D points of origin in bloodstain patterns.

What does 'B = tanA' signify in blood evidence analysis?

A method for determining angles or distances based on bloodstain evidence.