Abio 175 exam 2

Coroner

Elected official who certifies death; no medical degree; does not perform autopsies

Medical Examiner (ME)

Appointed doctor who investigates deaths and performs autopsies

Forensic Pathologist

Medical specialist who performs autopsies and determines cause/manner/time of death

Autopsy Evidence

Clothing, nail scrapings, hairs, DNA swabs, bullets, GSR, trace evidence

Autopsy Documentation

Clothing damage, scars, tattoos, medical intervention signs, medical records

Injury Documentation

Classify wounds, photograph, measure, X-rays, projectile path, bone damage

Internal Examination

Y-incision, organ removal/weighing, microscopic exam, stomach contents, toxicology

Scene Investigation

Photograph body, collect evidence, estimate time of death, remove body properly

Time of Death Indicators

• Body changes

• decomposition

• insects

• overdose signs

• weapon distance

Blunt Force Trauma

Injury from dull object causing

• abrasions

• contusions

• lacerations

Contusion

Bruise from ruptured blood vessels under skin

Laceration (Blunt Force)

Irregular tear with tissue bridges and bruising

Fracture

Break or separation of bone

Dislocation

Bone forced out of normal joint position

Pattern Injuries

• Seat belt marks

• treadmarks

• steering wheel patterns

• photographed at 90°

Sharp Force Trauma

Well-defined cuts from knives or blades; stabs, chops, incisions

Defensive Wounds

Injuries on hands/arms from victim protecting themselves; good for DNA swabs

Asphyxiation

Anything interfering with oxygen intake; look for facial injuries and bruising

Strangulation

Ligature or manual; possible hyoid damage; defensive wounds

Hanging

Death from vessel compression or neck injury; document noose/knot position

Hyoid Bone

Rarely fractured in suicide; more common in homicidal strangulation

Gunshot Wounds

Firearm injuries; distance of fire critical

Entrance Wound Ranges

Distant, intermediate, close, contact

Tattooing/Stippling

Powder marks indicating distance of gunshot

Soot

Black residue indicating close or contact shot

Collaring

Tissue ring around bullet entry wound

Angled Entrance Wound

Crescent bruise showing bullet direction

Contact Gunshot

Soot inside wound, barrel marks, stellate tears

Close Range Gunshot

Tight stippling pattern 1–2 inches

Intermediate Gunshot

Wide stippling 4–12 inches

Distant Gunshot

No soot or stippling; dark color from drying

Homicide

Non-accidental death caused by another person

Suicide

Person intentionally causes their own death

Accidental Death

Unintentional death (falls, crashes, overdoses)

Natural Death

Death from disease or internal medical cause

Undetermined Death

Insufficient evidence for category

Rigor Mortis

Stiffening begins ~5 hrs, full at 30 hrs, ends ~36 hrs

Decomposition Signs

Green abdomen (24–36 hrs), bloating (2–3 days), corneal clouding, marbling

Forensic Entomology

Using insect life cycles to estimate time of death

Blood Spatter

Pattern created when blood is deposited on a surface

Bloodstain Pattern Analysis

Uses science to determine what happened during bloodshed

Blood Components

RBCs (no DNA), WBCs (DNA), platelets, plasma

Coagulation

Blood clots in 15–20 minutes; serum separates

Blood Viscosity

Blood is 5–6x thicker than water

Surface Tension

Blood forms spherical drops due to molecular attraction

Spines

Lines extending from a blood droplet

Satellite Spatter

Small droplets near main stain

Convergence

2D point where blood drops originated

Angle of Impact

Determined by stain shape; shows direction of travel

Area of Origin

3D location of blood source using angle + convergence

Passive Blood Stains

Drops formed only by gravity

Transfer Blood Stains

Bloody object contacts another surface; may show patterns

Transfer Pattern

Shape of object visible in blood transfer

Individual Characteristics

Unique wear patterns identifying specific item

Projected Blood Stains

Impact, forward, back spatter

Low Velocity Spatter

Large drops; passive; <5 ft/sec

Medium Velocity Spatter

5–25 ft/sec; from blunt force

High Velocity Spatter

Mist-like; >100 ft/sec; often gunshots

Back Spatter

Blood from entrance wound traveling toward shooter

Drawback Effect

Blood sucked into gun muzzle from entrance wound

Cast-Off Pattern

Blood flung from a weapon in motion

Arterial Spray

Blood spurting from damaged artery; bright red

Void Pattern

Missing blood area where object blocked spatter

Skeletonization

Dried edges of stain; indicates movement or cleaning

Expirated Blood

Blood blown from mouth/nose; may contain bubbles

Neulander Case

N.Y. Ex-Doctor Who Claimed His Wife Died by Slipping in the Shower at Their Mansion - was later convicted of murder after a second trial - serving 20 years to life

Jodi Arias

convicted of first-degree murder in the slaying of her ex-boyfriend Travis Alexander

point A

where was this victim attacked? (point A or B)

Hard surfaces

smooth stains

textured surfaces

spines/satellites

How long has this woman been deceased?

• rigir mortis

• 5-36 hours

How long has this man been deceased?

• Decomposition

• marbling of the skin

Deductive Reasoning

Process of drawing a conclusion

based on known facts or

premises

• Be patient

• Consider all evidence

• Listen to your experts

Manner of Death

Circumstances that led to a fatal result; classified into 5 categories.

Homicide

Non-accidental death caused by another person through negligence, recklessness, or intent.

Suicide

Person intentionally causes their own death.

Accidental

Unintentional death such as traffic accidents, overdoses, or drownings.

Natural

Death caused by disease or internal medical conditions.

Estimating Time of Death

Pathologist uses body/scene characteristics to approximate time of death.

Time of Death Indicators

Witness accounts, temperature, scene conditions, mail dates, meal/dishes.

Algor Mortis

Body cooling after death until reaching room temperature.

Algor Mortis Rate

Loses ~2°F first hour, then 1–1.5°F per hour until ambient temperature.

Algor Mortis Factors

Ambient temperature, humidity, clothing.

Average Body Temp

Oral temperature ~98.6°F (37°C).

Livor Mortis

Settling of blood toward gravity; begins ~20 min, fixed by 16 hours.

Lividity

Skin discoloration from pooled blood (pink-red or deep purple).

Blanching Test

Pressing lividity area; blanches if within 16 hours, no blanching if past 16 hours.

Livor Mortis Movement Indicator

Different lividity patterns show body was moved.

Livor Mortis Impressions

Objects/clothing leave permanent blanching patterns after 16 hours.

Rigor Mortis Muscle stiffening starting

~5 hours postmortem; disappears ~36 hours.

Rigor Mortis Progression

Begins in head/neck, moves to extremities; occurs in all muscles.

Rigor Mortis Cause

ATP depletion prevents muscles from relaxing.

Rigor Mortis Sign

Skin may appear to have goosebumps.

Decomposition

Breakdown of body due to microorganisms after death.

Green Discoloration

Appears on abdomen after 24–36 hours.

Corneal Clouding

Cloudy eyes appearing early in decomposition.

Marbling

Vein patterning on skin from decomposition in lower abdomen.

Inductive Reasoning

Reaching a conclusion based on limited evidence.

Objectivity

Lack of bias; essential for accurate crime scene reconstruction.

Falsifiability

Attempting to disprove your theory rather than prove it.