Week 13 - Forensic Anthopology

Decompositional Processes

the postmortem decomposition process driven primarily by bacteria, producing discoloration, gas formation, tissue liquefaction, and characteristic odors.

Putrefaction

1. Autolytic and Bacterial Decay

2. Early Post-Mortem Changes

3. Gas and Fluid Production

4. Insect and Scavenger Attraction

Putrefaction

Type of Decay:

• anoxia

• enzymes

• cellular breakdown

Autolytic delay

Type of Decay:

• enteric

• environmental

bacterial decay

Types of Early Post Mortem Changes

1. Rigor Mortis

2. Livor Mortis

3. Algor Mortis

Types of Gas and Fluid Production

• Noxious

• Malodorous

T/F: Mummification involves the dehydration of organs and tissues as well as drying and shriveling of remains

True

Mummification Requirements

• dry conditions

• hot or cold

Hydrolysis of subcutaneous fat tissue - adipocere or “grave wax”

Saponification

Saponification requirements

• moisture

• anaerobic environment

• High Ph

Who was involved in Time Since Death - the Postmortem Interval

Dr. William M. Bass

Types of Burials in Anthropology

• prehistoric

• historic

• forensic

basic biological profiling includes

• age

• sex

• ancestry

• statute

the study of bones, focusing on their structure, development, function, and the changes they undergo during life and after death

Bone osteology

1. bone is living tissue

2. hardest connective issue

3. withstands tension and compression forces (6-10 times normal stress)

4. high survivability

Bone Characteristics

Parts of the Skeletal System

1. Cranial Skeleton

2. Axial Skeleton (torso)

3. Appendicular Skeleton

Cranial Skeleton

• skill

  • cranium

  • mandible

  • teeth

Axial Skeleton

• hyoid

• sternum

• ribs

• vertebrae

Appendicular Skeleton

• arms and hands

• shoulder girdle

• legs and feet

• pelvic girdle

Dentition Types

• Deciduous Dentition - 20 teeth

  • Permanent Dentition - 32 teeth

Tooth Types

• incisors

• canines

• premolars

• molars

Appendicular Skeleton: Upper Extremities

• Scapula

• Clavicle

• Humerus

• Radius

• Ulna

• Carpals

• Metacarpals

• Phalanges

Appendicular Skeleton: Lower Extremities

• Innominate

• Sacrum

• Femur

• Patella

• Tibia

• Fibula

• Tarsals

• Metatarsals

• Phalanges

Places with Growth Plates

• elbow

• hip

• ankle

• knee

• wrist

• shoulders

• clavicle

Growing Long Bone Components

• Epiphysis (2)

• Metaphysis (2)

• Diaphysis (1)

• + Epiphyseal plate (growth plate)

Mature Long Bone Components

• Epiphysis (2)

• Metaphysis (2)

• Diaphysis (1)

• + Epiphyseal line

2 Stages Used to Determine Age

1. Developmental (formative)

2. Degenerative (deteriorative)

• Long bone lengths

• dentition and dental eruption

• epiphyseal union (fusion)

• Degenerative changes in skeleton (bone breakdown)

• Public symphysis degeneration (the surface morphology of the public symphysis changes with age)

Methods for Determining Age

Parts of the Body used for Sex Estimation

• cranium

• pelvis

T/F: the skill is the best area for sex estimation (accuracy ~90%), with the pelvis as next best (accuracy ~80%)

False - Pelvis is the best

T/F: Generally, the male skull is more robust and muscular than the female

True

Pelvis Sex:

• opening is smaller, more obstructed

• Pubic arch is V shaped

Male Pelvis

Pelvis Sex:

• opening is larger and less obstructed

• Pubic arch is U shaped

Female Pelvis

Forensic race determination

estimating the ancestry of unknown skeletal remains

Types of Timing for Trauma in the Skeleton

• Antemortem (before)

• Perimortem (during)

• Postmortem (after)