crim 356 midterm

Death is described in three ways

1. Manner of death

2. Medical cause of death

3. mode/mechanism/instrument of death

Investigative jurisdiction

• In BC, we have a coroner system (governed by the BC Coroner’s Act) 

Manner of death = five categories: 

1. Homicide

2. Suicide

3. Accidental

4. Natural

5. Undetermined

Medical causes of death = specific disease or injury as specified by…

• ICD-11 (International Classification of Diseases 11th revision)

Exsanguination

loss of blood

Asphyxiation

loss of air

cardiac arrest

heart attack

What is forensic anthropology?

• Subfield of physical (or biological) anthropology

• Aids in death investigations by helping determine the manner, medical cause, and instrument of death 

What is forensic science? 

• The application of science to matters of law

• Forensic comes from the Latin word forensis: public, to the forum or public discussion; argumentative, rhetorical, belonging to debate or discussion. A relevant, modern definition of forensic is: relating to, used in, or suitable to a court of law.

Membership in the forensic anthropology sections 

• The role of the anthropologist is to apply methods and theories from the discipline of anthropology to aid death investigations in various contexts (e.g., medicolegal, human rights violations, forensic recoveries) 

What are skeletons?

• Hard internal or external framework of bones, cartilage, or other rigid material

• Mineral storage: 99% calcium and 85% phosphorus

• Attachment site for muscles and ligaments to effect movement

Vertebrate skeleton

the internal bony or cartilaginous framework found in humans and other backboned animals that enables movement and shields vital organs

invertebrate skeleton

The outer shell or hard structure (exoskeleton) found in insects and crustaceans is made of materials like chitin

Four types of variation in human skeletal anatomy

1. Ontogeny (growth)

2. Sexual dimorphism (biological sex)

3. Geographic or population-based

4. Idiosyncratic (individual)

1. Ontogeny (growth)

Size and shape from fetus to adult

2. Sexual dimorphism (biological sex)

• Size and shape differences between males and females

3. Geographic or population-based

geographic affinity

4. Idiosyncratic (individual)

Normal variation between different individuals of the same age, sex and population 

Bone is a composite tissue

• 35% organic component: type 1 collagen

• 65% inorganic component (minerals) : Hydroxyapatite

Fossilization (Process):

1. Organism 

Dies and is covered⬇

2. Rapid burial

Over time, pressure⬇

3. Fossil

Gross anatomy

Immature bones are the first to form prenatally, replaced by mature bone as growth continues.

At the gross level, the adult skeleton has two basic structural components

1. cortical

2. trabecular or cancellous tissue

cortical

• (the outer, denser envelope which plays a major structural support function) “compact bone”

• (80% of the body)

1. trabecular or cancellous tissue

•  (the metabolically more active form which is structurally like a fine sponge with numerous small voids) “spongy bone”  

• (20% of the body)

Fetal growth

• Ossification

• Fontanel

ossification

the natural biological process of bone formation where specialized cells called osteoblasts replace soft tissues, like cartilage, with hard bone

Fontanel

commonly known as a "soft spot," is a membrane-covered gap between the bones of an infant's skull

Bone remodelling

 old bone is removed by osteoclasts and replaced by osteoblasts 

Bone remodelling cycle

1. Basic multicellular unit (BMU) = temporary team of bone cells that work together to remodel and repair tissue

2. Osteoclasts (bone-removing cells)

3. Osteoblasts (bone-forming cells)

4. Osteocytes (controller, listener, communicator)

bone cycle 2.0

1. Activation (Resting to Remodelling)

2. Resorption (Breaking Down Bone)

3. Reversal (Transition)

4. Formation (Building New Bone)

Retrievable information from skeletal record

• Macroscopic analyses: age, sex, geographic affinity, injury, disease, genetic traits, taphonomy

• Microscopic analysis (histology)

• DNA and biomolecular analyses

• Isotopic analysis

• Radiographic analyses 

• Medical imaging: X-ray, MRI, computed tomography

what is taphonomy

the scientific study of what happens to the remains of plants and animals from the moment of death until their discovery as fossils or decayed material

Epiphyseal union

• After birth, bone growth occurs in cartilaginous “plates”

  • Cartilage cells divide by mitosis for growth

  • Basic molecular units (BMUs) enter via the bloodstream

  • Minerals are deposited, and bone ossifies 

Observations over time

1. Ossification

   1. Markers of growth

2. Maturation

   1. BMUs remodel bones

3. Antemortem 

   1. Injuries or events before death

4. Permimortem

   1. Injuries or events at or near the time of death

5. Postmortem

   1. Observe damage to the body after death

6. Fossilation

   1. Mineralization 10k+ years

Antemortem 

Injuries or events before death

Perimortem

Injuries or events at or near the time of death

Postmortem

damage to the body after death

Sex estimations

• Pelvis = most reliable

Female pelvic bones tend to be:

• Less robust

• Pelvic inlets are wider

body differences in male and female

trait	Male	female
Pelvic inlet	Heart shaped	oval/circular
Subpubic angle	Narrow (<90 degrees)	Wide (>90 degrees)
Greater sciatic notch	Narrow (maximal expression)	Wide (minimal expression)
Ventral arc	Usually absent	Usually present

subpubic angle in women vs men

male = Narrow (<90 degrees)

women = Wide (>90 degrees)

ventral arc

• Females have a ‘ventral arc’ which is a flattened, roughly triangular-shaped

• Aspect to the ventral (anterior) surface of the pubic symphysis 

 iliopubic ramus differences

• In females, the iliopublic ramus (part of the bone connecting the ilium to the pubic bone) is long relative to the diameter of the acetabulum.

• In males, the length of the ilipoubic ramus and the diameter of the acetabulum are roughly equivalent dimensions.

When you’re dealing with the skull, you deal with two types of bones

• Facial

• Cranial

Impacts on bone formation/remodelling

• Old age - osteoporosis (too much bone taken away, not enough put back - thin, brittle bones)

• Malnutrition

• Disease - rickets (vitamin D deficiency) causes long bones to grow warped; scurvy (vitamin C deficiency) causes:

• Injuries - will require bone remodelling to fix the break, rather than simply maintenance

• Extreme use/sports - when you build more muscles around the bone, it actually causes more bone to form

Syphilis

= STI caused by bacterium Treponema pallidum (TP)

• Pitting or porous lesions on the skull

• Irregular new bone formation

• Destructive lesions that alter normal bone surface

• Targets bones that are rich with blood supply

Osteoarthritis

• Osteoarthritis is the most common form of arthritis, caused by the gradual breakdown of protective joint cartilage that cushions bone ends

Look for:

• Lipping around joint margins

• Polished joint surfaces

• Bone spurs (osteophytes)

• Enlargement of joint surfaces

Tuberculosis

a rare and serious infection where tuberculosis bacteria spread from the lungs through the bloodstream into the bones and joints

Pott’s disease (Spinal TB)

• this is the most frequent form, affecting the vertebrae and adjacent discs

  • Causes spinal deformities - such as fa forward curvature (kyphosis/hunchback), sometimes paralysis

Tuberculosis arthritis:

• infection in weight-bearing joints like the hips and knees destroys cartilage, narrows joint spaces, and reduces mobility, eventually causing permanent joint stiffness or fusion

TB tends to produce:

• Irregular bone destruction

• Rounded cavities

• Little new bone formation compared with other infections

• Unlike pyogenic bacterial infections, TB often leaves bone looking ‘moth-eaten’ rather than heavily thickened

Spina Bifida of the sacrum

• Congenital defect in which the posterior (back) part of one or more sacral vertebrae fails to fuse completely during development

Spina Bifida typical signs

• Missing spinous processes

• A midline cleft in the posterior sacrum

• Exposure of the sacral canal

• Smooth bone margins, indicating a developmental anomaly rather than trauma

Brucellosis of the vertebrae

Also called brucellar spondylitis, it is an infection of the spine caused by Brucella bacteria, usually acquired from infected animals or unpasteurized dairy products

Anterior vertebral body erosion (Pedro Pons sign)

• This is considered a classic feature

  • Destruction occurs at the anterosuperior corner of a vertebral body

  • Creates a localized erosive defect

  • Often accompanied by surrounding sclerosis (dense bone formation)

Polio (poliomyelitis) (legs)

• Is a highly infectious,vaccine-preventable viral disease caused by the poliovirus that attacks the nervous system and can cause permanent paralysis or death?

• Polio does not directly infect bone tissue, but the nerve and muscle damage it causes leads to significant, long-term structural changes in the skeleton.

• Preventable, but no cure

Aquatic death

•  may be any manner of death - not just accidental

Drowning process

1. Water enters lungs

2. Damaged lining

3. Alveolar collapse

4. Red blood cells and proteins enter alveoli (pulmonary edema)

Expanded drowning process 

1. Voluntary breath-holding (apnea) as the victim struggles to maintain position above or near the surface of the water 

2. Breaking point, gasping, involuntary inhalation of water. Sometimes includes a spasm of the upper airway

3. Swallow large amounts of water. Sometimes, vomiting with aspiration of gastric contents into the lungs

4. Hypoxemia within minutes unless there's an intervention. Lose consciousness. Develop brain/cerebral hypoxia and seizures

5. Involuntary loss of urine, feces, seminal fluid (sometimes with great pain)

6. Respiratory arrest, cardiac arrest, then death.

Non-drowning examples

• Sequestered - to be stuck in something

• Medical 

• Secondary locations - when people die somewhere else but are tossed into the ocean

Drowning is a diagnosis by exclusion

• No singular test that tells you this is the cause of death

• You need to test other causes of death to conclude drowning

Stages of decomposition

1. Terrestrial - on land

2. Aquatic - in water

Terrestrial stages (continuum is relatively predictable)

• Involves the breakdown of proteins, carbohydrates, and fats (scavenging, insect colonization, autocatalysis & putrefaction)

1. Fresh

2. Bloated

3. Active decay

4. Advanced decay

5. Dry remains/sketal

Aquatic stages - Continuum is highly dependent on the depositional environment 

1. Fresh

2. Bloated if conditions are met

3. Active decay if conditions are met

4. Advanced decay if conditions are met

5. Dry remains/skeleton if conditions are met

Below 62 m (200 ft), likely won't bloat. Why?

1. Tidal action prevents insect colonization 

2. Clothing may inhibit bloating

3. Cold temperatures inhibit bacterial growth

4. High pressure prevents expansion of bacteria-produced gases

5. scavengers/trauma cause torso damage

6. Decompositional gases are easily compressed and water-soluble

Barotrauma

 pressure-induced trauma

conjunctiva

The conjunctiva is a clear mucous membrane covering the white of the eye (sclera) and lining the eyelids

sclera

he tough, white, fibrous outer layer of the eyeball itself

Petechial hemorrhages

small, round, red or red-brown spots on your sclerae and conjunctivae

• Caused by increased pressure within the venous system (esp. Veins in the head and neck)

• Indicative of increased pressure (associated with asphyxia deaths)

Other ocular changes

1. Tache noir

   1. Means this could be a secondary location

2. Lazy eyelid

3. Corneal opacity/clouding

Rigor mortis

Degrees of rigour - scale of 1 - 10

ATP depletion leads to muscles stiffening

(peaks approx. 12 h after death, lasts 24 hrs or so)

Descriptors of rigour mortis

1. Not detectable (absent)

2. Not yet fully established (partial)

3. Fully established (full, complete)

4. Leaving the body (passing)

Factors that speed rigour

1. Excessive environmental heat,

2. hypothermia,

3. disease or infection,

4. physical activity perimortem,

5. seizures,

6. poisioning

Livor mortis

red, blue or purple marbling (discolouration) due to gravitational pooling of blood

• Blanching = focal absence of lividity due to compression against an object or surface

• Can be bright pink, or cherry red in deaths involving carbon monoxide, cyanide, hypothermia, or certain types of poisioning

• Note impacts of water pressure, blood loss, bruising, and water movement (currents, postmortem movement)

Happens (approx. 12 h after death)

Algor mortis

 cooling of the body to the surrounding (ambient) temp of the depositional environment

• In aquatic deaths, take the temperature from the core (into the liver or rectum) by C/ME.

happens (approx. 1 degree F/hr over first 12 hours)

Factors impacting your estimation:

• Extreme temperature

• Cold water immersion

• Clothing

• Body habitus

• Weather

• Temperature

• Drug use

• Medications

• Medical conditions

Saponification

formation of adipocere (grave wave) in wet, anaerobic environments

Osteometric assessments

taking precise measurements of bones to study their size, shape, and proportions.

• Done in the lab

Morphological assessments

systematically examining what someone's body or physical features look like.

• done in the field

Differences between assessments

• Morphological assessments - subjective to the person who's doing them (observational)

• Osteometric assessments - more expensive; need fancier equipment; bones used for this are really old - missing elements/fragmented, so you can’t take measurements as well because you don’t have the whole bone.

Early postmortem changes and soft tissue decay

• Decompositional pathway

  • Autolysis (enzymatic self-digestion) and putrefaction (bacterial breakdown causing marbling and bloat)

• Mortis triad

Preservation states and differential decay

• Mummification

• Saponification

• Bog bodies

• Differential decomposition

mummification

• desiccation in arid/dry environments

saponification

•  formation of adipocere (grave wave) in wet, anaerobic environments

bog bodies

•  acidic, anaerobic peat preservation 

differenetial decomposition

• = irregular decay indicating infection, checmical/heat exposure, and/or trauma 

Bone diagenesis & enviro. Modification

• Diagenesis

• Skeletal weathering

• Environmental artifacts

diagenesis

• chemical and physical post-depositional alterations to bone

Skeletal weathering

6-stage progression based on the Behrensmeyer scale (0-5), driven by solar radiation and thermal/moisture cycles

Environmental artifacts

root etching, metallic discoloration (e.g., copper = green, iron = rust orange), soil staining 

Scavenging against and bone trauma

• Entomology = knowledge of blow fly oviposition/instects helps to establish PMI; dermestid beetles arrive during dry decay

• Carnivores = chew bones and cause: punctures, pits, scoring and furrows (predictable destruction sequence)

• Rodents = paired parallel striae from gnawing with incisors

• Vultures = cause rapid skeletonization (approx. 3- 24 h) with minimal bone markings left behind 

Disarticulation and transport

• Terrestrial = animal scavenging and connective tissue breakdown can result in movement either through gravity or intentionally through scavenging

• Fluvial (aquatic) transport = sink/float cycles driven by putrefactive gas buildup

• Disarticulation sequence = hands, mandible from skull, limbs, pelvis 

Estimating postmortem interval (PMI)⬇

1. Primary method is to use internal temperature rates (>80% rate variation)

⬇

2. Accumulated degree days (ADD) = thermal heat accumulation above 0 degrees C threshold

⬇

3. Total body score (TBS) = quantitative anatomical scoring system, applied to regression models

⬇

4. Multidisciplinary tools: forensic entomology, marine biology (barnacles/algae), botany (root growth)

What are specific taphonomic and forensic factors? 

• Location of body 

• Clothing

• weather/climate

• What scavengers are present in said environment