bloodstain pattern analysis
What are the four main types of bloodstains?
Passive, transfer, projected/impact, and miscellaneous.
What are expiratory patterns in bloodstain analysis?
Patterns caused by blood from an internal injury mixing with air expelled from the lungs.
What are projected bloodstain patterns?
Patterns produced by blood released under pressure, typically larger than passive drop stains.
What method can be used to determine the 3D origin of a bloodstain pattern?
Placing strings at the base of each bloodstain and projecting them back to the axis.
What is pooling ?
Pooling occurs when gravitational forces pull blood to the lowest possible level and an accumulation of blood develops
What must be established to determine the original distance from the wall or floor in a bloodstain pattern?
The impact angles of representative bloodstains and their trajectories back to a common axis.
What does clotted blood explain ?
The presence of clots within a bloodstain pattern may indicate that some time elapsed between the event that resulted in bloodshed and clot formation
What is bloodstain pattern analysis (BPA)?
The science of examining and interpreting blood present at a bloodshed event to determine what events occurred, in what order, and who possibly left the stains.
What should be documented when analyzing bloodstains?
The size, shape, and distribution of stains and patterns, along with photographs and sketches.
What is the significance of the tail in measuring the length of a bloodstain?
The tail is not included in the measurement.
What influences the shape and size of bloodstains?
The texture of the target surface affects the size and shape of the bloodstain pattern.
What is the purpose of reconstruction in bloodstain analysis?
To evaluate the aftermath of bloodshed to determine the actions that created the bloodstains.
What is viscosity in relation to blood?
Viscosity refers to the thickness of blood, which affects how slowly it flows. The more viscous a fluid, the more slowly it flows
What is a swipe in bloodstain patterns?
When a bloodied surface rubs across a non-bloodied one.
What is a wipe in bloodstain analysis?
When a non-bloodied surface moves through or across a stationary bloodstain.
What are Sharp force injuries?
smaller surface area, less blood transfer to weapon, smaller and more linear pattern of bloodstains
What is Blunt force injuries?
surface area, generally larger weapons used, varying size of bloodstain drops
What are the 3 primary areas pertaining to the blood stains?
1. Size 2. Shape 3. Distribution of the bloodstains
What is the area of convergence in bloodstain pattern analysis?
A 2-D point where an imaginary line drawn through the long axis of each bloodstain in the direction opposite of observed travel intersects.
How much blood does a normal healthy adult have?
Approximately 4.5-6.0 liters, which makes up 7-8% of their body weight.
What is high velocity impact spatter (HVIS)?
Caused by high velocity impacts, such as gunshots, resulting in fine mist patterns.
What distinguishes low velocity impact spatter (LVIS)?
Caused by minimal force, typically produced by gravity, such as blood dripping or splashing.
What shape does a bloodstain generally take when blood impacts a target surface at 90 degrees?
Circular.
What is directionality in bloodstain patterns?
Directionality refers to the direction that the blood was traveling, indicated by the narrow end of an elongated bloodstain.
What are passive bloodstains?
Drips, flows, clots, and blood pools that result from blood dripping into blood.
What type of bloodstains are created when blood strikes a target at an angle less than 90 degrees?
Elliptical bloodstains.
What is a skeletonized stain?
Forms when the center of a dried bloodstain flakes away, leaving a visible outer rim.
What characterizes medium velocity impact spatter (MVIS)?
Caused by a medium velocity impact, typically from an intense beating or blunt force.
What occurs in a flow pattern of bloodstains?
A change in the shape and direction of a bloodstain due to gravity or movement of the surface.
What is a drip pattern in bloodstain analysis?
A pattern resulting from blood dripping into blood, usually striking the surface at a 90-degree angle.
What is back spatter?
Blood directed towards the source of energy that caused the spatter, often seen in gunshot wounds.
What is the shape of a blood drop when it falls?
Blood falls in a spheroid configuration due to surface tension.
What is an arterial spurt/gush?
Blood projected from a breached artery, creating individual stains with varying amounts.
What is the drying process of bloodstains?
Bloodstains dry from their perimeter inward toward the center.
What is a cast-off pattern?
Cast off patterns are those created when blood is released or thrown from a blood-bearing object in motion
What is a transfer bloodstain?
Indistinct stains that can be any size or shape, created when a bloodied surface contacts a non-bloodied one.
What happens to blood when it leaves the body?
It clots and precipitates within minutes.
What does the drying time of blood depend on?
It depends on the volume of blood, the surface it lands on, and the environmental conditions.
What does the area (point) of origin indicate?
It is a 3D point that indicates where the blood event originated.
What is a void pattern in bloodstain analysis?
Occurs when an individual or item is between the area of impact and the surrounding surfaces.
What is the significance of the shape of bloodstains?
Shape is a chief source of information that can indicate the direction of travel and the dynamics of the bloodshed event.
What is forward spatter?
Small drops of blood traveling with a bullet through the exit wound.
