What causes blood shunting? what is blood shunting.
A High velocity spatter is generally caused by a gunshot wound but can be from a wound from another type of weapon if enough force is used. Once the type of velocity is determined it’s important to determine the angle of impact.
Based on the varying sizes and shapes of the blood drops, investigators can often tell what type of weapon caused the spatter, determine the general area where the attack occurred, and track the positions of the victim. … “Oftentimes blood spatter analysis is used to test an alibi, such as self-defense,” Johnson says.
Several factors influence the appearance of satellite spatter, including the blood drop volume, freshness of blood, surface texture, and distance of the vertical target from the impact site.
Blood behaves not unlike those spilled water droplets, and the speed at which the droplets travel when they strike a surface, known to analysts as a target, affects their shape. These are usually caused by gunshot wounds, but they can also result from explosions, power tools or high-speed machinery. …
The spherical shape is caused by the surface tension of the blood. Surface Tension causes the blood drop to pull itself in; both horizontally and vertically. The blood drop will settle into a spherical shape, as a result of the surface tension.
- Saturation Pattern – Bloodstain pattern resulting from an accumulation liquid on an absorbent material.
- Target – A surface upon which blood has been deposited.
- Terminal Velocity – The greatest speed to which a free falling drop of blood can accelerate in air; This speed is 25.1 ft/sec.
Analysts or investigators will typically soak up pooled blood, or swab small samples of dried blood in order to determine if it is human blood and then develop a DNA profile. This becomes critical when there are multiple victims.
Bloodstain-pattern analysis has been accepted as reliable evidence by appellate courts in one state after another with little or no examination of its scientific accuracy. … Once one court ruled such testimony admissible, other states’ courts followed suit, often citing their predecessors’ decisions.
To spatter means to scatter small particles of a substance. A spatter is the pattern of drops that result from spattering. To splatter means to scatter large particles of a substance. A splatter is the pattern of drops that result from splattering.
Blunt force injuries (hitting or beating) – objects inflicting this type of injury are usually larger, such as a bat or hammer. If the object impacts liquid blood, the larger surface area will collect more blood, producing drops of varying sizes.
As the angle of impact is made smaller or more acute, the bloodstain pattern will become more elongated, elliptical, or oval in shape. The resulting bloodstain’s shape will indicate the direction of travel for that stain and thus, the origin of the drop of blood.
The first hypothesis that the higher the blood is dropped from, the bigger the spatter it will create is correct. Since there is more time due to the greater height there is more impact from gravity pulling the drop down which makes the drop gather more speed so it hits the surface with more force.
Overall, the results indicated that the application of kinetic energy of between 1 and 5J at a height of 1780mm led to the blood droplets travelling a maximum horizontal distance of 5361mm (and average maximum distance of 4981mm).
Cast-Off Pattern — A bloodstain pattern created when blood is released or thrown from a blood-bearing object in motion. Directionality — The directionality of a bloodstain or pattern which indicates the direction the blood was traveling when it impacted the target surface.
When drops of blood hit the floor at an angle, they produce elliptical stains, where their width-to-length ratio gives that impact angle. Traditionally practitioners of blood-pattern analysis trace a straight-line from the stain at the impact angle to reveal where the blood originated.