LECTURE 3: FORENSIC ANTHROPOLOGY // CHAPTER 8

Question 1

Define forensic anthropology

Answer 1

• identification of human (can be animal) remains (fresh, partially or completely decomposed) for legal purposes
• uses osteology, anatomy, metrics, and radio imaging to identify individual and cause and mechanism of death

Question 2

The role of a forensic anthropologist

Answer 2

Biological identification

• species
• gender/ sex
• age
• biological group/ethnicity
• stature
• pathology

Personal identification

• odontology
• pathology
• emispheric dominance
• genetics
• facial reconstruction
• provenancing
• post-mortem interval

Question 3

determining sex

Answer 3

• male/female pelvis
• female pelvis is wider with longer horizontal diameter
• femoral and radial head diameter
• femoral (female < 43mm) (male > 48mm)
• radial (female < 21mm) (male > 23mm)

all are either greater/smaller and equal

Question 4

determining age

Answer 4

• public symphysis
  hip bones change with age - ridges in the bone disappear and the boarder becomes less defined
  in old age pitting occurs
• Iscan method
  examination of the 4th left rib
  starts smooth and changes with age
• Clavicle medial epiphysis
  examination of the clavicle - flakes form over age stages

Question 5

determining ancestry

Answer 5

• skull measurements
• Femoral Head Torsion Angle (with reference to diaphysis and condyles): wide in asians, very small to none in negroids, intermediate in caucasoids.
• shape of hair when cut in a cross-section
• skin distribution of pigment

Question 6

determination of stature

Answer 6

• formulas/tables based on long bone length or vertebral body height
• only an estimation as living people have soft tissue

Question 7

Post mortem interval

Answer 7

• Time since death / how long the body has been dead
• 4 stages:
  • Fresh body
  • Bloating, skin slippage, imperfection
  • Much body lost and draining of fluids, decomposition
  • Skeletonization

Question 8

4 main functions of skeleton

Answer 8

1) Support – provides infrastructure for attachment and support of softer tissues
2) Motion – these attachments allow bones to acts as levers
3) Protection – bones protect soft organs from physical damage
4) Growth – bones are centres for growth and RBC production, readily available calcium source

Question 9

1) Endochondral ossification

Answer 9

• Bone grows by replacing cartilage
• Growth starts with a ‘model’ of a bone consisting of cartilage and centres of ossification
• From these centres bone is produced and infiltrates the cartilage model
• Developing shaft (diaphysis) and ends (epiphysis)
• These areas then meet and bone knits together
• Not all epiphysis unite at the same time – can be used for estimating age for those below 25 years old

Question 10

2) Intramembranous ossification

Answer 10

• Bone grows from mesenchymal connective tissue

- Ossification occurs within a membrane rather than cartilage

Question 11

Bone cells

Answer 11

Osteoblasts:
- produce bone (osseus tissue) and deposit it in layers
Osteocytes:
- maintain matrix
Osteoclasts:
- Resorb and remodel bone as required for growth - these are giant, multinuclear, phagocytic, and osteolytic cells

Question 12

Sex determination - Pelvis

Answer 12

METHOD MALE FEMALE

Pelvis in general Large, rugged Smaller, gracile

Subpubic concavity Narrow Wide

Acetabulum Large Medium to small

Sciatic notch Narrow Wide

Preauricular sulcus Absent May be present

Ventral arc Absent or very small Present, can be strongly

Subpubic concavity Absent/shallowPresent/can be deep

Ischiopubic ramus. Thin, narrow Wide, possible ridge

Question 13

Sex determination - Cranium

Answer 13

• Males tend to be larger with more muscle attachments
• Areas of interest:
   Brow ridges, mastoid processes, occipital area, upper palate, general architecture
• Metric enthusiasm extends to determination of sex
• Measurements are taken with specialised rulers (callipers – either spreading callipers or sliding callipers)
• Take references and compare against reference population’
• Postcranial bones can help but most info is from measurements – quantitative measures

Question 14

Determining age - Pubic symphysis

Answer 14

• Is the junction of the two pubic bones lying roughly 4-5in below the navel
• The junction is bridged by cartilage that acts as a cushion bet the two bones
• The symphyseal surface is a raised platform that changes from a rough, rugged surface to a smooth well-defined area
• Considered most reliable morphologic indicator of age at death

Question 15

Determining age - Ribs

Answer 15

• Sternal end of end of fourth left rib

- As cartilage between rib and sternum ages, it begins to ossify at a known an predictable rate

Question 16

Determining age - Sacroiliac joint

Answer 16

• Changes in auricular surface where ilium attaches to sacrum (sacroiliac joint)
• As age progresses the surface of bone becomes less bumpy and more smooth, with smallish pores opening up – a decrease in the surface organisation traits

Question 17

Determining age - Remodelling

Answer 17

• Constantly remodelling in response to stresses placed on it, seen in the microscopic structure of bone
• Constant erosion and renewal of bone leaves permanent markers in bone and once we die, these changes cease – correlation between the amount of bone reworking and the amount of time the body has expended energy on this remodelling
• Sample taken – microscope; whole osteons, fragmented osteons, interstitial bone fragments – only downside is taking the sample off evidence, may not be allowed due to case requirements

Question 18

Determining ancestry - skull

Answer 18

• White, black, Hispanics, Asians, native American, other
• Can be estimated by morphological or quantitate analysis – both centred around skull
• Morphological features
   General structure
   Eye orbits
   Nasal aperture
   Dentition
   Surrounding bones of face
   Scooped-out appearance of lingual side of upper central incisors (often found in Asian ancestry) // some native Americans show shovel-shaping on incisors
• Metric means of categorising human populations was established
• Fairly accurate but based on historic populations not modern populations

Question 19

Determining Stature

Answer 19

• Length of long bones, especially lower limb

- Sex and ancestry are required to correctly estimate – as humans vary within and between these categories

Question 20

Cause vs. manner of death

Answer 20

• Cause is the action that initiates cessation of life

- Manner is the way in which death came about: natural, accidental, suicide, homicide

Question 21

Odontology

Answer 21

• Conducted by comparisons of dental remains to either antemortem or post-mortem records – antemortem comparison are most common
• Forensic dentist produces post-mortem records by descriptions of dental structures and taking radiographs
• Comparison between post and ante can then be done
• Fillings, gaps and restorations are main points of identification or even good hygiene and few restorations
• Noting similarities and discrepancies