Forensic Final

Algor Mortis

postmortem decline in body temperature

Rigor Mortis

postmortem stiffening of muscles caused by chemical changes (ATP)

Livor mortis

postmortem pooling of body fluids in the lowest body areas due to gravity after circulation stops

How does bloating occur

gas produced by bacterial fermentation of the liquified tissues

comingling

mixing together of skeletal remains from more than one individual due to mass graves, disaster scenes (plane crashes) etc.

Minimum Number of Individuals (MNI)

estimate the lowest possible number of people or animals present in a fragmented skeletal assemblage

Pathology

• A disease, injury, or abnormal condition that changes the normal structure or function of body tissues/organs and negatively affects the individual

• can be born with or acquired

Postmortem Interval (PMI)

• the amount of time that has passed since a persons death

• helps determine:

  • when death occurred

  • timeline of events in a case

  • whether witness/alibi statements match the evidence

Accumulated Degree Days (ADD)

• sum of the average daily temperatures (in Celsius) that a corpse experiences

• time it takes to turn a body to skeleton = 1285/ADD (ex. if 40 degrees, body will skeletonize in 32 days {1285/40 = 32})

Callus

• new bone tissue that forms around a fracture while the bone is healing

• bulge/thickened area around the break

• irregular extra bone growth where healing occurred

beveling

cone-shaped, angled bone erosion produced when a projectile (like a bullet) passes through flat bone, such as the skull

kerf mark

groove created in an object that is being cut by the saw teeth

keyhole defect

steep angle gunshot wound, characterized by a rounded entry and wider exit (beveling

purge

release/leaking of decompositional fluids from the body’s natural openings after death

gnawing

• chewing or biting on the bone

• often leaves the ends of the bone looking ragged, crushed or rounded off

pits

• shallow, small, rounded dents in the bone surface

• made when a tooth presses down into the bone but doesn’t drag across it

• looks like little puncture marks

furrows

• longer, deeper grooves usually found near the ends of bones

• form when canids chew and crush softer parts of bone repeatedly

• often caused as they work to break open bone ends for marrow

scoring

• thin, shallow scratch-like lines on the bone surface

• created when teeth drag across the bone while pullinh/tearing flesh

punctures

deep, narrow wound caused by a pointed object penetrating the cortical layer of the bone (ice pick, animal teeth, needle)

plug and spall

blunt force trauma where impact causes a piece of bone (plug) to be driven inward or outward at the point of impact, while the opposite side of the bone fractures and flakes (spall) due to transmitted force

Low-velocity trauma

• slow loaded force permits bone to respond and compensate for an increase in stress (SFT, BFT))

• when the stress is removed, the bone may:

  • return to its original shape

  • remain deformed

  • fair

High-velocity trauma

bone does not experience or adjustment; it merely shatters due to energy absorbance (gunshot, explosion)

Puppe’s Law

• fracture lines in bone stop when they meet a pre-existing fracture line

• helps determine the order in which injuries occurred

Drift (water recovery)

analysis of how currents, tides, wind, and decomposition stages influence the movement and final location of human remains in aquatic environments.

CSI effect

phenomenon where popular crime television shows (like CSI) create unrealistic expectations among jurors regarding forensic science/criminal investigation

Facial reconstruction

last-resort identification technique combining anthropology, anatomy and artistry to recreate a face from skeletal remains, often when other methods fail

excavation

digging and removal of soil/material to uncover buried evidence, remains or artifacts

scene mapping

the process of measuring, recording and documenting the layout and location of evidence within a crime/death scene

Disarticulation

separation of bones at their joints after decomposition or trauma:

• soft tissues break down

• joints loosen

• animal scavenging

• environmental disturbances

Canid carnivore scavenging

feeding and disturbance of human remains by meat-eating animals, especially members of the dog family

Ground Penetrating Radar (GPR)

• non-invasive geophysical method that uses radar waves to detect and image subsurface disturbances or buried objects beneath the ground

• instead of “seeing objects,” GPR mostly shows changes in density, buried shapes etc.

cadaver dogs

• detect chemicals released during human decomposition

• detect specific odor compounds from skin, blood, tissue breakdown etc.

what 5 things should be on every crime scene mapping

1. north arrow

2. scale

3. project

4. site

5. location