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antemortem trauma - answer -injury to a body that occurs during life. anthropologist can determine this by the presence of scars or callus at the site of fractures
increased porosity near break
Rounded edges
Callus presence Perimortem Trauma - answer -occurring at or around the time of death
Sharp edges
Hinging
Fracture lines
Angular broken edges
Hematoma Staining postmortem trauma - answer -after death
No fracture lines
No green stick and hinge fractures
Break occur at angles of shaft
Dark inside Blunt force trauma - answer -injury caused by force over wide area Types of blunt traumas - answer -Blunt objects
Vehicle crashs
Abrasion
Bites
Falls laceration - answer -wound or injury with jagged, irregular edges and flesh still attached near edges contusion - answer -bruise Abrasion - answer -Superficial removal or stretching of skin radiating fracture - answer -pattern of cracks that move outward from a point of impact concentric fracture - answer -circular pattern of cracks that forms around a point of impact
buttressing - answer -Blows at the cranial cause fractures around
Mid-occipital
Posterior temporal
Anterior Temporal
Midfrontal LeFort I - answer -most common, low horizonal fracture LeFort 2 Fracture - answer -Blunt force around nose, entire midface separation LeFort 3 Fracture - answer -Upper face, seperation of entire face What affects damage caused by blunt force trauma - answer -Size, shape, weight, force, angle, intent Bullet Caliber - answer -Diameter of bullet Bullet guage - answer -Weight of a lead ball Ex.
12 gauge - can hold 1/12th of a pound Bullet jacket - answer -Usually a metallic cover over the core of a bullet. Usually cooper
Semi jacketed
Non jacket - Deform on impact bullet point - answer -Sharp - Rifle
Blunt - Hand gun
Hollow point - Indentation in tip so exapnd on impact Hard contact of gun causes - answer -stellate scar Loose contact - answer -Soot, small burn area, rarely stellate scar Muzzle burn Close range - answer -No muzzle burn Soot area is bigger, stippling >7 inches - answer -Stippling, no soot, spread inward beveling - answer -- outer part of the hole is smaller than the inner part of the hole
- entrance wounds outward beveling - answer -seen in wounds at the site of a bullet's exit from the body keyhole wound - answer -Bullet strikes bone on tangent, causing both entrance and exit wound in the same area Bullet wound fracture lines - answer -Going fast or high caliber incision - answer -wound with neat, clean edges that is longer than deep Puncture wound - answer -Wound that is deeper than long Cleft wound - answer -Result of combination of both sharp and blunt trauma
- Break bones
- Remove and chew bones
Marks on bone, rodent and teeth marks Teeth puncutre - answer -Tooth penerate bone Pitting - answer -Teeth dont penetrate bone Scoring Scoring - answer -Shallow grooves Furrow - answer -Deep groove Burning changes - answer -Shrinkage of bone, discoloring based on heat Weathering - answer -Sunlight causes bleaching, shrinking and warping Water Transportation - answer -lighter, less dense, rounder objects float away
Heaver, denser, flatter objects do not move far Three main elements of firearms that have direct effects on bone - answer -- Size
- Construction
- Velocity Goals of ballistics - answer -- The nature of the trauma may provide evidence as to:
- Type of firearm (handgun, rifle, shotgun, other)
- Characteristics of the projectile (size and composition)
- Position of shooter relative to victim (distance, orientation)
- Sequence of wounds (number, sequence) Absence of signs of projectile trauma - answer -Absence of evidence of projectile trauma on bone does not eliminate possibility of projectile trauma to an individual, as it could have just missed the bone Three main types of firearms - answer -- Handguns (single projectile) GSW
- Rifles (single projectile) GSW
- Shotguns (multiple projectiles) SGW Size - answer -The diameter of a projectile and/or barrel of a weapon (from .05" to .5") Determining size of a firearm - answer -The size of a projective or weapon barrel is measured in terms of caliber, gauge, or number Type of size for different firearms - answer -- Caliber for handguns and rifles
- Gauge and number for shotguns (with one exception: .410 bore shotgun). Caliber - answer -Diameter of bullet or barrel of handgun or rifle measured in hundredths of an inch or mm. Determination of caliber - answer -- Determination of caliber is complicated by the fact that the actual diameter of bullets is sometimes less or greater than that advertised by their manufacturers
- Shotguns are more complicated because their barrel diameters are measured in gauges, while the pellets they expel are measured by number Gauge - answer -The maximum weight of a lead ball that would fit down the barrel of the weapon (ex: 10 gauge = 1/10th of a pound ball) Number - answer -Number refers to pellet size, either birdshot or buckshot Pellets - answer -Solid balls made of lead and steel
Determining pellet size - answer -- Pellet size denoted by birdshot/buckshot number, linear relation btwn birdshot number & pellet size (ex: #12 shot has .05" diameter, #11 shot has .06" diameter)
- Buckshot numbers range from 4-0/00, but the relationship between pellet size and buckshot number is not linear (#3 buck = .25, #1 buck = .30)
- Shotgun ammunition designed to expel 1 oz of pellets independent of size (00 buck holds 9 pellets that equal 1 oz, #6 birdshot holds 225 pellets that equal 1 oz) Bullet construction - answer -Projectile shape, internal composition, and covering (jacketing) of a bullet Three basic bullet profiles - answer -- Sharp
- Blunt
- Hollow-point Effects of different bullet profiles - answer -- Sharp profile: rifle ammunition
- Blunt and hollow-points: handguns
- Blunt and hollow-point bullets most likely to deform on impact and cause larger wounds in bone (especially exist wounds)
- This is especially true with hollow-points which expand when hitting and traveling through a target Two types of internal bullet compositions - answer -- Solid lead
- Fragmenting (explode on contact, encase pellets that scatter throughout the target when the bullet hits) Jacket - answer -- A thin copper coating on a bullet
- Jacketing reduces deformation and fragmentation, so non-jacketed bullets are more likely to deform bone while passing through tissue Full-metal jacket - answer -A jacket that covers the entire projectile Semi-jacket - answer -Jacket that covers only part of the bullet Velocity - answer -The speed at which the projectile hits its target Impact of velocity on wounds - answer -- Velocity has the greatest effect on wounding power (since KE is proportional to the square of velocity).
- Catastrophic wounds are more indicative of high rather than low velocity projectiles, which gives indications of type of weapons
- Rifles generally produce higher velocity bullets than regular handguns Breakdown of velocity - answer -- After penetration, internal damage proportional to square of bullet velocity (v) and mass (m)
- KE = mv
- Greater the mass the greater the energy (Double mass = double KE)
- Greater the speed the greater the energy (Double speed = 4x increase KE) Energy and tissue damage - answer -- Wound severity relates directly to amount of kinetic energy transferred from bullet to tissue
- This may be less than the total amount of kinetic energy of the bullet, unless the bullet does not exit body, in which case all energy is expended in the tissue Rifling - answer -Spiral grooves cut into the internal surface of barrels and running from one end to the other
Round bullet wounds - answer -Circular in outline Oval bullet wounds - answer -Elliptical in outline Keyhole bullet wounds - answer -Have the appearance of old-fashioned keyholes, circular on one end and triangular on the other Irregular bullet wounds - answer -Wounds that do not show any general pattern Four factors that influence the shape a bullet produces - answer -- Construction
- Angle of trajectory
- Angle of axis
- Type of wound (entry or exit) that it forms When round wounds are likely - answer -- When both the angle of trajectory and the angle of bullet axis are perpendicular to the bone's surface
- In entry wounds
- In the smaller opening of the wound's bevel
- Any bullet construction causes a round entry wound, but a round exit wound is caused by jacketed projectiles because they are non-deforming When oval wounds are likely - answer -- When angle of trajectory not perpendicular to bone's surface or when the bullet is tumbling when it strikes (indicative of deflection)
- In entry wounds
- On the smaller opening of the bevel
- Jacketed projectiles more likely to create oval entry/ exit wounds, but any construction can cause this type of entry wound When keyhole wounds are likely - answer -- Caused by bullets that graze bone, so angle of trajectory is extremely acute with little penetration (both exit and entry wounds)
- Fairly round entrance defect with inward beveling with a splayed out triangular exit wound with outward beveling connected to it
- Most common in the cranial vault
- Can originate from any type of bullet Using keyhole wounds to determine direction of fire - answer - When irregular wounds are likely - answer -- Can take on a variety of configurations, from jagged circular to asymmetric stellar to irregular rectangular
- The result of shattering that gives the appearance of a bone that has exploded
- More characteristic of exit wounds (though not always)
- Blunt and hollow-point bullets (soft-tipped projectiles) cause irregularity Most important characteristics that affect wound size - answer -- Wound type
- Bullet characteristics Effect of wound type on wound size - answer -Exit wounds are larger than entry wounds Effect of bullet size on wound size - answer -- Large-caliber ammunition causes larger wounds
- Soft-tipped, hollow-point bullets cause larger wounds
- .22 generally has larger wound than .25-caliber bullet
- .25 likelier to be jacketed and thus less likely to deform
- Greater flattening of the .22 bullet because of its smaller size when impacting relatively thick bone
- Considerable overlap btwn wounds from all calibers
Reasons for larger-than-caliber entrance wounds - answer -Related to bone thickness, as thick bones cause bullets to deform more and cause larger entry wounds Reasons for smaller-than caliber entry wounds - answer -- In young individuals bones are pliable enough to bend in slightly at bullet impact, causing a smaller hole when the bone snaps back into place
- If the bullet collides with an intermediate object before striking the victim the bullet may fragment before entry, causing a smaller entry hole
- Passage of a bullet through a suture or pre-existing fracture line can cause smaller holes Overview of fracture lines - answer -- Impact of bullets on bone can form fracture lines
- More powerful weapons cause more extensive fracturing
- Only research done on fracturing for the skull vault, bones of the thorax, and long limb bones Radiating fracture lines in the cranial vault - answer -- Originate at site of impact and move outward in any direction, following areas of weakness in vault bones
- When lines encounter a foramen or other fracture line they stop or follow the suture line for a while before continuing in the original direction Concentric fracture lines in the cranial vault - answer -- Appear as part or all of circle whose center is at the point of bullet impact
- Caused by intracranial pressure from bullet passing through skull/compresses soft tissue in front of it
- Occurs later in fracturing sequence, so power can be dissipated and stopped when it encounters radiating fracture lines
- Production of concentric lines dependent on power of weapon and due to externally beveled projectiles Two different types of fracture lines that occur on long bones - answer -- Butterfly fractures
- Irregular fractures Cavitation - answer - Butterfly fractures on long bones - answer -- Occur around site of bullet impact on diaphyses, appear as lozenge-shaped lines extending along the long axis of the bone
- When the bullet strikes near the center of the bone these fractures are bilateral, but if the bullet strikes away from center, fractures may be unilateral Irregular fractures on long bones - answer -When a bullet exits long bone it generally shatters the bone outward such that no pattern can be discerned (causing irregular fracture lines) Overall purpose of bullet wound analysis - answer -- Bullet wounds can be analyzed to determine info about the victim and its relation to the victim
- Because of variability in ammunition and impact on bone, information must be general 7 Steps in bullet wound analysis - answer -- Description of wounds
- Estimation of caliber
- Estimation of bullet construction
- Estimation of velocity
- Estimation of direction of fire
- Estimation of sequence
- Miscellaneous estimations Description of wounds - answer -- First step in bullet wound analysis
