Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Forensic Bio Ch. 4
Crime Scene Reconstruction: Bloodstain Pattern Analysis
| Question | Answer |
|---|---|
| method used to support a likely sequence of events by the observation and evaluation of physical evidence | crime-scene reconstruction |
| what all can bloodstain pattern interpretation uncover | direction blood originated, angle droplet struck, location/position of victim @ time of incident, movement of bleeding person, # of blows stuck on victim, location of person delivering the blows that produced bloodstain pattern |
| A drop of blood that strikes a surface at an angle of impact of approximately 90 degrees will be close to (elliptical, circular) in shape. _________. | circular |
| how do you determine the angle of impact of a blood stain | Sin A=width of blood stain/length of blood stain |
| spatter projected outward and away from the source; created when a projectile creates an exit wound | forward spatter |
| spatter projected backward from the source; created when a projectile creates an entrance wound | back spatter (blow-back spatter) |
| the space in two dimensions to which the directionalities of spatter stains can be retraced to determine the location of the spatter-producing event | area of convergence |
| how is area of convergence established | drawing straight lines through the long axis of several individual bloodstains, following line of their tails |
| the space in three dimensions to which the trajectories of spatter can be utilized to determine the location of the spatter-producing event | area of origin |
| used at a crime scene to approximate the position of the area of origin using angles of impact of individual stains in the pattern | string method |
| fine forward spatter from an exit wound and back spatter from an entrance wound | gunshot spatter |
| when back spatter may strike the gunman and enter the gun muzzle | drawback effect |
| spatter pattern created when blood-covered object flings blood in an arc onto a nearby surface | cast-off |
| a bloodstain pattern resulting from the ejection of blood under hydraulic pressure, typically from a breach in the circulatory system | projected pattern |
| a bloodstain pattern resulting from blood forced by airflow that is expelled from the mouth or nose from an internal injury | expiration pattern |
| pattern created when an object blocks the deposition of blood spatter onto a target surface or object leaving an absence in an otherwise continuous bloodstain pattern | void |
| list the types of spatter patterns | spurt/projected, cast-off, drip trail, impact, expectorate/mist, drips |
| series of drops that are separate from other patterns, formed by blood dripping off a moving object/injured person | drip trail |
| occurs when an object strikes liquid blood | impact spatter |
| blood drops from a stationary object | drips |
| list they types of non-spatter patterns | gust/splash, smear, pattern transfer, blood in blood, wipe, swipe, saturation, pool, flow |
| blood is ejected in volume | gust/splash |
| transfer from one object to another through contact and lateral movement | smear |
| transfer that imparts a recognizable characteristic | pattern transfer |
| drips deposited into one another | blood in blood |
| made when an object moves through a pre-existing stain | wipe |
| transfer from a blood object to another through lateral motion | swipe |
| accumulation created by contact with an absorbent material | saturation |
| occurs when blood collects in a level (not sloped) and undisturbed place due to gravity | pool |
| bloodstain resulting from the movement of a volume of blood on a surface due to gravity or movement of the target | flow |
| colloidal fluid suspension of materials and viscous fluid or liquid | blood |
| a smaller bloodstain that originated during the formation of the parent stain as a result of blood impacting a surface | satellite stain |
| the angle (alpha), relative to the plane of the target, at which a blood drop strikes the target | angle of impact |
| a bloodstain resulting from an airborne blood drop created when external force is applied to liquid blood | spatter pattern |
| a bloodstain pattern resulting from an object striking liquid blood | impact pattern |
| a bloodstain resulting from contact between a blood bearing surface and another surface | transfer stain |
| an altered stain consisting of its edge characteristics, the central area having been partially or entirely removed | perimeter stain |
| uses a grid of known dimensions that are set up over the entire pattern | grid method |
| uses a rectangular border of rulers that are set up around each pattern and a smaller ruler next to each stain | perimeter ruler method |
| Reconstructing the circumstances of a crime scene is a team effort that may include the help of law enforcement personnel, medical examiners, and _________. | forensic scientist |
| Generally, bloodstain diameter (increases, decreases) with height. | increases |
| The _________ and _________ of blood striking an object may be discerned by the stain’s shape. | direction; angle of impact |
| _________ is the most common type of blood spatter found at a crime scene and is produced when an object forcefully contacts a source of blood. | impact spatter |
| Movement of a bloody object across a surface, (lightens, darkens) as the pattern moves away from the point of contact. _________ | lightens |
| The edges of a bloodstain generally dries within _____ seconds of deposition and are left intact even if the central area of a bloodstain is altered by a wiping motion. | 50 |
| Which of the following is of paramount importance in the interpretation of bloodstain patterns? a. The direction of impact b. The surface texture c. The angle of impact d. The amount of blood | b. The surface texture |
| How can an investigator tell the direction of travel of blood from the shape of a bloodstain? | the tail of an elliptical stain, any sort of distorted edge, and any satellite stains |
| What is the difference between the shape of a bloodstain that impacts a surface at a low angle and one that impacts at a higher angle? | bloodstains at a lower angle have more elongated shapes with longer tails |
| What is the difference between forward spatter and back spatter? Which is more likely to be deposited on the object or person creating the impact? | forward spatter is a spatter that is projected outward away from the source while back spatter is projected backward from the source and is more likely to be deposited on the object/person creating the impact |
| In general, as both the force and velocity of impact increase, what happens to the diameter of the resulting blood droplets? | it decreases |
| Name three factors that affect the amount of backward spatter produced by a gunshot wound. | location of injury, size of wound, and distance from muzzle |
| What determines the size of blood drops in a cast-off pattern? | the type of object (small pointed surface will have smaller w/ linear pattern while large blunt surface will have large drops and wide pattern), volume of blood (less or more blood), nature of swing (speed, angle, etc.) |
| Name two ways to distinguish expirated blood from other types of bloodstains. | lighter color with bubbles in it |
| How might a void pattern be useful to investigators? | identifying the size and shape of objects or persons and determining positions during the incident |
| Explain how the shape of stains in a trail pattern can help investigators determine the direction and speed at which a person was moving. | the direction of the tails is based on the pointed end, this shows the direction in which the blood stain traveled giving the direction of the person moving. They can also show speed. The more elongated, the faster the person was moving |
| the mount of spatter from a blood droplet falling on a hard, nonporous surface is ________ that of a drop of blood of equal size, falling from the same distance, onto a softer, porous surface | less than |
| if a murder victim's blood is found in the muzzle of a firearm: a) can be concluded the firearm is the murder weapon b) can be concluded the owner of the firearm is the perpetrator c) can be concluded the firearm was present during injury to the victim | c) can be concluded the firearm was present during injury to the victim |
Created by:
hbhull05