Gabrielle Tucker
Nov 12, 2024
Bloodstain Patterns: Projected Patterns
● Projected Stains are created by blood expelled from a source under pressure
○ Known as “dynamic stains”
○ Examples:
■ Arterial spurting patterns
■ Castoff patterns
■ Impact spatter patterns
Arterial Spurting:
● Results from blood exiting the body under pressure from a breached artery
● Pattern shows a spike indicating cardiac contracting followed by a valley
● As victim loses blood , the spikes get shallower and closer together , and finally
disappear
● If a large blood vessel is severed or lacerated , a person can bleed to death in one
minute or less
Cast-off Patterns:
● Created when blood is projected onto a surface , usually the ceiling and walls , from
a blood object in motion
● Generally associated w/ blunt or sharp force trauma
● First blow causes skin to rupture and bleed; no cast-off
● Subsequent blows are contaminated w/ blood which is flung off by centrifugal force
● Experts use cast-off patterns to determine how many blows were struck and if the
attacker was right or left handed
Impact Spatter:
● Categorized by the speed of the initial force that sets the blood in motion
● Traditionally referred to as low , medium , and high velocity impact spatter
● Many pd’s no longer use these terms , referred to as impact spatter
Low Velocity Impact Spatter:
● Created by force ranging from normal gravity to movement up to 5 feet
● Produced as a bleeding person walks or runs , dripping blood as they go , or blood
dripping from a weapon
Nov 12, 2024
Bloodstain Patterns: Projected Patterns
● Projected Stains are created by blood expelled from a source under pressure
○ Known as “dynamic stains”
○ Examples:
■ Arterial spurting patterns
■ Castoff patterns
■ Impact spatter patterns
Arterial Spurting:
● Results from blood exiting the body under pressure from a breached artery
● Pattern shows a spike indicating cardiac contracting followed by a valley
● As victim loses blood , the spikes get shallower and closer together , and finally
disappear
● If a large blood vessel is severed or lacerated , a person can bleed to death in one
minute or less
Cast-off Patterns:
● Created when blood is projected onto a surface , usually the ceiling and walls , from
a blood object in motion
● Generally associated w/ blunt or sharp force trauma
● First blow causes skin to rupture and bleed; no cast-off
● Subsequent blows are contaminated w/ blood which is flung off by centrifugal force
● Experts use cast-off patterns to determine how many blows were struck and if the
attacker was right or left handed
Impact Spatter:
● Categorized by the speed of the initial force that sets the blood in motion
● Traditionally referred to as low , medium , and high velocity impact spatter
● Many pd’s no longer use these terms , referred to as impact spatter
Low Velocity Impact Spatter:
● Created by force ranging from normal gravity to movement up to 5 feet
● Produced as a bleeding person walks or runs , dripping blood as they go , or blood
dripping from a weapon
