Dr Tim Thompson RFPLecturer in Forensic Anthropology

Anatomy & Forensic Anthropology, School of Life Sciences, University of Dundeet.j.u.thompson@dundee.ac.uk www.tjuthompson.com

Heat-induced Changes tothe Human Body and theImplications for Positive

Identification

Contents

1. Burned Human Remains andForensic Anthropology

2. General Heat-induced Changes in theHuman Body

1. The Soft Tissues2. The Hard Tissues

3. The Implications for HumanIdentification

4. Conclusions

Attitudes in Anthropology

I would straight away place on record my consideredopinion, based on experience, that cremated remains

of human bones in burial urns are almost alwaysdevoid of any anthropological interest … From an

anthropological point of view, therefore, these bonesare of no scientific value, and I consider that nothing

is lost if they are neither submitted to nor preserved inthe Museum.

Professor CM FurstChief Inspector of Antiquities in Stockholm, 1930s

We are not starting from a happy place…

Contexts Surrounding Burned Remains

Anthropological Interest (archaeological, enthnographic, forensic & medico-legal)

The Story So Far…

Limited understanding due to lack of coherent, continuous research

McKinley, J.I. 1993 Bone Fragment Size andWeights of Bone frm Modern British Cremations andthe Implications for the Interpretation ofArchaeological Cremations. International Journal ofOsteoarchaeology 3: 283-287.

McKinley, J.I. 1994 Bone Fragment Size in BritishCremation Burials and its Implications for PyreTechnology and Ritual. Journal of ArchaeologicalScience 21: 339-342.

McKinley, J.I. 1994b The Anglo-Saxon Cemetery atSpong Hill, North Elmham. Part VIII: TheCremations. East Anglian Archaeology Report No.69: GB.

McKinley, J.I. 1998 Archaeological Manifestations ofCremation. The Archaeologist 33: 18-20.

McKinley, J.I. 2000 Phoenix Rising: Aspects ofCremation in Roman Britain. In: Pearce, J., Millett,M. and Struck, M. (eds.) Burial, Society and Contextin the Roman World. Oxbow Books: GB. Pp38-44.

McKinley, J.I. and Bond, J.M. 2001 Cremated Bone.In: Brothwell, D.R. and Pollard, A.M. (eds.)Handbook of Archaeological Sciences. John Wileyand Sons, Ltd.: GB.

Mayne Correia, P.M. 1997 Fire Modification ofBone: A Review of the Literature. In: Haglund, W.D.and Sorg, M.H. (eds.) Forensic Taphonomy: ThePost-mortem Fate of Human Remains. CRC Press,Inc.: USA. Pp275-293.

Mayne Correia, P. and Beattie, O. 2002 A CriticalLook at Methods for Recovering, Evaluating, andInterpreting Cremated Human Remains. In:Haglund, W.D. and Sorg, M.H. (eds.) Advances inForensic Taphonomy: Method, Theory, andArchaeological Perspectives. CRC Press, Inc.: USA.Pp435-450.

Kennedy, K.A.R. 1996 The Wrong Urn:Commingling of Cremains in Mortuary Practices.Journal of Forensic Sciences 41(4): 689-692.

De Gruchy, S. and Rogers, T.L. 2002 IdentifyingChop Marks on Cremated Bone: A PreliminaryStudy. Journal of Forensic Sciences 47(5): 933-943.

Tomita, M., Ijiri, I., Shimosato, K. and Mikami, Y.1984 The Effect of Heating on Y-chromosomeDetection. Forensic Science International 24: 43-49.

Heat & the Integumentary System

First layer of contact with the source of the heat

SkinErythema and blistersHeat contractureAM vs PM damage

Keratinous TissueHair and nails‘Clubbing’

Spontaneous Human Combustion

Explaining the urban legend…

Heat & the Internal Organs

The Muscles‘Pugilistic attitude’

The Respiratory TractInhalation of hot gases

The Internal OrgansVisceraBrain

Surviving these injuries

Damage to the soft tissues inevitably affects positive identification

Heat & the Blood

The constituents of blood are severely affected by heating and fires

Heat-induced changes to the bloodRed blood cell breakdownHeat haematomaAM vs PM damage

Toxins in the bloodCarbon Monoxide (CO)CyanideOther toxins

4 Stages of Heat-induced Degradation

As described by Mayne Correia (1997) and revised by Thompson (1999)

Stage Description Approximate TemperatureRange (°°°°C)

Dehydration Removal of Water 100-600

Decomposition Removal of OrganicComponents 500-600

Inversion Removal of Carbonates 700-1100Fusion Melting of Crystals 1000+

Secondary Heat-induced Change

Examples of secondary heat-induced change

0

20

40

60

80

100

120

Pre-

burn

ing

500o

C 1

5min

s 5m

ins

500o

C 1

5min

s 15

min

s

5 00o

C 1

5min

s 25

min

s

5 00o

C 4

5min

s 5m

ins

500o

C 4

5min

s 15

min

s

5 00o

C 4

5min

s 25

min

s

7 00o

C 1

5min

s 5m

ins

7 00o

C 1

5min

s 15

min

s

7 00o

C 1

5min

s 25

min

s

7 00o

C 4

5min

s 5m

ins

7 00o

C 4

5min

s 15

min

s

7 00o

C 4

5min

s 25

min

s

9 00o

C 1

5min

s 5m

ins

9 00o

C 1

5min

s 15

min

s

900o

C 1

5min

s 25

min

s

9 00o

C 4

5min

s 5m

ins

900o

C 4

5min

s 15

min

s

9 00o

C 4

5min

s 25

min

s

Burning Conditions

Num

ber o

f Mea

sure

men

ts R

ecor

ded

4 Stages of Heat-induced Transformation

Redesigning Mayne Correia (1997) and Thompson (1999)

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

Dehydration

Decomposition

Inversion

Fusion

Temperature (°°°°C)

The intricate inter-relationship between the heat-induced changes

1200

1100

1000

900

800

700

600

500

400

300

200

1000

Temperature (°°°°C)

Dimensional Change

Porosity Change

Recrystallisation

Changes in Strength

Fracture Formation

Weight Loss

Colour Change

Modeling Heat-induced Change

Heat-induced Dimensional Change

Here we see both the presence of H-i expansion and shrinkage

Dimension 500oC15mins

500oC45mins

700oC15mins

700oC45mins

900oC15mins

900oC45mins

5 Minutes 1.94 1.2 1.64 2.44 5.52 5.3515 Minutes 1.96 1.39 1.81 2.92 5.56 5.57D125 Minutes 1.96 1.5 1.95 3.34 5.69 5.765 Minutes 0.9 0.88 4.25 19.33 7.29 14.45

15 Minutes 0.86 1.47 4.86 5.58 8.03 15.16D225 Minutes 0.87 1.83 5.23 6.24 9.1 15.715 Minutes 0.79 -4.53 -1.72 3.07 6.52 36.18

15 Minutes 10.13 -3.84 -1.1 4.4 7.4 37.06D325 Minutes 0.84 -3.19 -0.37 5.22 8.73 37.685 Minutes -1.59 1.15 14.09 5.24 19.15 14.62

15 Minutes -1.59 1.15 14.6 6.88 20.54 16.2D425 Minutes -1.46 2.06 15.68 8.67 21.55 16.475 Minutes 2.67 3.04 7.02 6.02 10.62 4.96

15 Minutes 2.7 3.61 7.57 6.88 11.59 10.39D525 Minutes 2.73 4.14 8.29 7.26 13.58 10.795 Minutes 0.93 6.57 3.88 4.1 5.67 -3.92

15 Minutes 1.06 7.35 5.1 5.06 6.77 -2.71D625 Minutes 1.06 8.04 5.82 5.85 7.94 -1.935 Minutes 2.34 10.15 11.64 7.32 15.26 -2.04

15 Minutes 2.4 11.16 12.45 8.53 16.64 -0.6D725 Minutes 2.4 13.04 13.59 9.57 21.12 0.155 Minutes 3.28 0.47 5.51 7.42 9 24.57

15 Minutes 3.35 1.28 6.25 8.32 10.04 25.4D825 Minutes 6.13 1.82 6.77 9.1 10.43 26.235 Minutes 6.83 -0.12 0.85 7.81 15.86 12.32

15 Minutes 6.94 0.98 1.97 9.12 17.99 13.66D925 Minutes 6.97 1.86 6.24 9.66 19.35 14.85 Minutes 5.79 -0.07 7.27 4.62 9.43 11.98

15 Minutes 5.84 0.83 8.02 5.74 10.63 13.17D1025 Minutes 5.77 1.72 9.52 6.47 11.66 13.765 Minutes 7.65 -0.45 5.24 5.92 11.81 18.18

15 Minutes 7.65 0.64 6.5 6.38 13.68 19.17D1125 Minutes 7.75 1.68 7.61 7.7 16.5 20.66

Influences on H-i Transformations in BonePrincipal Component

1 2 3 4 5Temperature 0.392 0.565 0.669 0.233 0.161

Duration -0.506 0.332 -0.099 -0.196 0.765% Weight loss -0.832 0.190 0.438 0.280 0.033

Number ofMeasurements -0.138 -0.890 -0.209 -0.357 -0.132

Crystal Size 0.257 0.517 0.533 0.210 0.582Skeletal Density 0.020 0.091 -0.940 0.300 -0.133

Bulk Density 0.676 -0.071 0.371 0.642 -0.158Microporosity 0.103 -0.223 -0.921 -0.269 -0.136Mesoporosity 0.096 0.934 -0.145 0.240 0.202Macroporosity -0.952 -0.116 -0.104 -0.241 -0.105D1 % Change -0.321 0.686 0.178 0.018 0.628D2 % Change 0.448 0.342 0.689 -0.015 0.455D3 % Change 0.766 0.182 0.248 0.153 0.544D4 % Change 0.985 0.094 0.123 0.068 -0.032D5 % Change -0.304 0.849 0.346 -0.259 0.023D6 % Change -.0941 -0.113 0.173 -0.193 0.188D7 % Change -0.876 0.297 -0.132 -0.356 0.036D8 % Change 0.148 0.091 0.355 0.194 0.898D9 % Change 0.351 0.075 0.199 0.911 0.034D10 % Change 0.680 -0.230 0.381 -0.427 0.397D11 % Change 0.025 0.376 -0.267 0.865 0.196

Major PCA associations (>0.550, <-0.550) are highlighted

A Unified System

Countering the false dichotomy between soft and hard tissues

Forensic vs Medicine vs ArchaeologyExperimentsPublicationsCollaborations

Body TissuesInfluence of soft on hard tissuesInfluence of hard on soft tissues

H-i Influences on Anthropological Methods

Heat-induced Change Technique Affected Cause of Effect

Colour Change MetricIndirectly: Colour changeimplies loss of organicswhich causes shrinkage

Weight Loss MetricIndirectly: Weight loss

implies loss of organicswhich causes shrinkage

Fracture Formation Morphological and Metric

Directly: Increasedfragmentation reduceslikelihood of technique

application

Changes in Strength Morphological and Metric

Indirectly: Weaker boneincreases fragmentation

which reduces likelihood oftechnique application

Recrystallisation Morphological and Metric

Directly: Changes inmicrostructure may affect

shape and will affectdimensions.

Porosity Change MetricIndirectly: Implies loss of

organics and reorganisationof microstructure.

Dimensional Change Morphological and MetricDirectly: Differential size

changes may affect shapeand will affect dimensions.

There is no way to avoid H-i changes when analysing burned bone

Predicting the Influence of Heating

DependentVariable Equation (using most appropriate variables) R2 Value

D1 % Change -D2 % Change -15.564 + 1.5 (Crystal Size) 0.848D3 % Change 25.726 - 468.258 (Macroporosity) 0.757D4 % Change 25.208 Š 311.342 (Macroporosity) 0.950D5 % Change -D6 % Change -1.750 + 242.815 (Macroporosity) 0.842D7 % Change 6.948 + 184.843 (Macroporosity) 0.751D8 % Change -10.615 + 1.426 (Crystal Size) 0.837D9 % Change -34.544 + 27.957 (Bulk Density) 0.737D10 % Change -D11 % Change -Temperature 207.015 + 31.850 (Crystal Size) 0.704

Duration -D1 % Change -1.023 + 0.131 (Duration) 0.789D1 % Change -6.273 + 0.131 (Duration) + 0.0075 (Temperature) 0.928

D1 % Change5.606 + 0.138 (Duration) Š 0.0607 (Number of

Measurements) Š 1.092 (Skeletal Density) + 0.01354 (%Weight Loss)

1.000

Linear regression equations [Note: dash indicates an equation could not be created]

Comparison of Prediction Equations

DependentVariable Prediction Equation R2 Value

D1 % Change Shipman et al (1984)0.302X3 + 0.0000826x2 + 0.0000000704x Š 0.688 0.775

D1 % Change This Research-1.023 + 0.131 (Duration) 0.789

D1 % Change This Research-6.273 + 0.131 (Duration) + 0.0075 (Temperature) 0.928

Additional variables improves description of sample

H-i Influences on Other ID Methods

Identification Technique Influenced by BurningHuman Bone Burning affects histology

Facial Reconstruction Facial bones shrink, distort and fractureDNA Destroyed Š but SNP and may survive in

micronichesOdontology Teeth suffer dimensional changes, fracture and

explodeFinger Prints Destruction of distal body parts

Ear Print Ears burned away

The potential of the British Association for Human Identification [www.bahid.org]

Conclusions

• Need to change attitudes in forensic anthropology andpathology with regard to the unification of the two tissuesystems and the identification information that can beextracted

• Need more basic data on the fundamental primary-levelheat-induced changes in bone

• Need a more coherent approach to all fire-orientedidentification research

• Refine and modify anthropological techniques of humanidentification

Relevant References

McKinley, J.I. 2000 The Analysis of Cremated Bone. In: Cox, M. and Mays, S. (eds.)Human Osteology: In Archaeology and Forensic Science. Greenwich Medical MediaLtd: GB. Pp403-421.

Mayne Correia, P.M. 1997 Fire Modification of Bone: A Review of the Literature. In:Haglund, W.D. and Sorg, M.H. (eds.) Forensic Taphonomy: The Post-mortem Fate ofHuman Remains. CRC Press, Inc.: USA. Pp275-293.

Thompson, T.J.U. in press Heat-induced Dimensional Changes in Bone and their Consequences for ForensicAnthropology. Journal of Forensic Sciences.

Thompson, T.J.U. 2004 Recent Advances in the Study of Burned Bone and their Implications for Forensic Anthropology.Forensic Science International 146S: S203–S205.

Hiller, J., Thompson, T.J.U., Evison, M.P., Chamberlain, A.T. and Wess, T.J. 2003 Bone Mineral Change DuringExperimental Heating: An X-ray Scattering Investigation. Biomaterials 24(28): 5091-5097.

Thompson, T.J.U. 2002 The Assessment of Sex in Cremated Individuals: Some Cautionary Notes. Canadian Society ofForensic Science Journal 35(2): 49-56.

Thompson, T.J.U. 2003 An Experimental Study of the Effects of Heating and Burning on the Hard Tissues of the HumanBody and the Implications for Anthropology and Forensic Science. Unpublished PhD Thesis, University of Sheffield.

Acknowledgements

This research formed the bulk of a doctoral project undertaken in the Departments ofForensic Pathology and Archaeology, University of Sheffield, UK. The practical aspectof this research could not have been achieved without the help, advice and time of thefollowing people: my supervisors Dr Martin Evison (Forensic Pathology) and Dr AndrewChamberlain (Archaeology); Erika Petersen (Archaeology, University of Sheffield) andRichard Stacey (Chemical and Process Engineering, University of Sheffield) providedaccess to the muffle furnaces; Ian Newsome (Forensic Pathology, University ofSheffield) the department’s digital photography equipment; David Jarvis (ForensicPathology, University of Sheffield) assisted with the radiography and John Proctor(Biomedical Sciences, University of Sheffield) likewise the electron microscopy; Dr ColinSmith (Palaeobiology, Museo Nacional de Ciencias Naturales, Madrid), Miranda Jansand Dr Matthew Collins (Biology and Archaeology, University of York) made availableand conducted the ground-breaking use of porosimetry and Dr Jen Hiller and Prof TimWess (Biological Sciences, University of Cardiff) the same with WAXS and SAXS.Current imaging work is being conducted with Dr Sandy Chudek. Thanks to Dr BeckyGowland (St John’s College, University of Cambridge) who gave advice and commentson the draft versions of this paper as well as throughout the research.

Thanks also to the International Association of Arson Investigators for allowing me theprivilege of presenting this research here.

Contact Details

Dr Tim Thompson

Unit of Anatomy & Forensic AnthropologySchool of Life Sciences

University of DundeeDow Street, Dundee, DD1 5EH, Scotland

T: +44 (0) 1382 344220E: t.j.u.thompson@dundee.ac.uk