perimortem and postmortem fracture patterns by...

PERIMORTEM AND POSTMORTEM FRACTURE PATTERNS

IN DEER FEMORA

by

CATHERINE SUSAN WRIGHT

A THESIS

Submitted in partial fulfillment of the requirements for the degree of Master of Arts

in the Department of Anthropology in the Graduate School of

The University of Alabama

TUSCALOOSA, ALABAMA

2009

ii

ABSTRACT

A question remains as to whether specific criteria can be used to differentiate perimortem

and postmortem breakage patterns in deer femora. The purpose of this experiment was to

discover if fracture characteristics, such as smooth or rough fracture surfaces, are statistically

correlated with bone condition (old, new) or bone end (proximal, distal). Two experimental

groups were used (postmortem; n = 46; perimortem; n = 41). Dependent variables (DV) were the

presence or absence of (a) right angles, (b) acute angles, (c) jagged edges, (d) curved edges, (e)

smooth bone surfaces, (f) rough bone surfaces, (g) transverse fractures, (h) butterfly fractures, (i)

number of fracture lines, and (j) number of pieces created from the break. Independent variables

(IV) were (a) the condition of the bone (old, new) and (b) end of the bone (proximal, distal). The

study hypothesis was that perimortem fractures would contain more acute than right angles and

more smooth than rough surfaces and that postmortem fractures would contain more right than

acute angles and more rough than smooth surfaces. A significant correlation among variables

may help future researchers to categorize unknown bones.

Bones were fractured using a Dynatup 8250 Drop Weight Impact Test Machine

(DWITM). New bones were tested within 2 days of receipt, and old bones at least 60 days

following receipt. Distal ends were secured in a vice, while proximal ends were placed on a foam

pad. Descriptive statistics, correlational analyses, and analysis of variance tests were conducted,

with an alpha level of p = 0.05 indicating statistical significance (two-tailed). Significant

correlations were observed between bone condition (old, new) and right angles (rho = -.463, p <

.001, old bones tend to exhibit a right angle); acute angles (rho = .415, p < .001, new bones tend

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to exhibit an acute angle); smooth bone surface (rho = .379, p < .001, new bones tend to exhibit a

smooth fracture surface); and rough bone surface (rho = -.420, p < .001, old bones tend to exhibit

a rough fracture surface). Results may be applicable to scientists in the fields of bioarchaeology

and forensic science.

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LIST OF ABBREVIATIONS AND SYMBOLS

df Degrees of freedom: number of values free to vary after certain

restrictions have been placed on the data

f frequency

F Fisher’s F ratio: A ration of two variances

M Mean: the sum of a set of measurements divided by the number of

measurements in the set

p Probability associated with the occurrence under the null hypothesis of a

value as extreme as or more extreme than the observed value

< Less than

= Equal to

v

ACKNOWLEDGMENTS

I am pleased to have this opportunity to thank the many colleagues, friends, and

faculty members who have helped me with this research project. I am especially indebted to Dr.

Kathryn Oths, the chairperson of this thesis, for sharing her research expertise and

wisdom regarding research writing, and statistical application. I would also like to thank all of

my committee members, Dr. Sharyn Jones, Dr. Jason Linville, and Dr. Bruce Wheatley for their

invaluable input, inspiring questions, and support of both the thesis and my academic progress. I

would like to thank Dr. Donna Burnett for her assistance in analyzing the statistical data and in

editing the thesis and Wade Rittenberry and Chris Robinson for assistance in editing. I am

especially thankful to Stephie Deitz for the beautiful photographs.

Dr. Alan Eberhardt provided the use of the Dynatup 8250 Drop Weight Impact Test

Machine to conduct the experiment through the Department of Biomedical Engineering at the

University of Alabama at Birmingham. Without his assistance, and that of his laboratory

engineers, this research would not have been possible.

Most of all, I want to thank Dr. Bruce Wheatley of UAB's Anthropology Department for

creating the original methodology for using the drop weight machine to conduct bone breakage

in similar experiments with deer bones. This methodology informed the design of the present

research. I would like to thank Dr. Wheatley's Advanced Physical and Forensic Anthropology

current and former students who, through class assignments, participated in the acquisition and

preparation of the bones for analyses through careful collection, cleaning, and processing.

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Without the diligence of these students in following Dr. Wheatley's methodology, results of Dr.

Wheatley's studies could not be used for comparison with the present study.

Finally, this research would not have been possible without the support of my friends and

fellow graduate students and, of course, my family members, who never stopped encouraging

me.

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CONTENTS

ABSTRACT ............................................................................................................ ii

LIST OF ABBREVIATIONS AND SYMBOLS .................................................. iv

ACKNOWLEDGMENTS .......................................................................................v

LIST OF TABLES ............................................................................................... viii

LIST OF FIGURES ............................................................................................... ix

1. INTRODUCTION ...............................................................................................1

2. LITERATURE REVIEW AND SIGNIFICANCE ..............................................5

3. METHODS ........................................................................................................14

a. Description of Study Sample .............................................................................15

b. Research Design and Procedures .......................................................................16

4. RESULTS ..........................................................................................................21

5. DISCUSSION ....................................................................................................47

6. CONCLUSIONS................................................................................................52

REFERENCES ......................................................................................................55

APPENDIX ............................................................................................................57

viii

LIST OF TABLES

4.1 Descriptive Statistics for Variables for Bone Characteristics ..........................22

4.2 Frequency and Percentage of Right Angles .....................................................23

4.3 Frequency and Percentage of Acute Angles ....................................................25

4.4 MANOVA Table for Right and Acute Angles ................................................28

4.5 Frequency and Percentages of Jagged Edges ...................................................29

4.6 Frequency and Percentage of Curved Edges ...................................................31

4.7 MANOVA Table for Jagged and Curved Edges .............................................33

4.8 Frequency and Percentage of Rough Surfaces .................................................35

4.9 Frequency and Percentage of Smooth Surfaces ...............................................37

4.10 MANOVA Table for Smooth and Rough Surfaces .......................................39

4.11 Frequency and Percentages of Transverse Fractures .....................................40

4.12 ANOVA Table for Transverse Fractures .......................................................41

4.13 Frequencies and Percentages of Butterfly Fractures ......................................42

4.14 ANOVA Table for Butterfly Fractures ..........................................................42

4.15 Descriptive Statistics for Variable: Radiating Fracture Lines .......................44

4.16 ANOVA Table for Radiating Fracture Lines .................................................45

4.17 Descriptive Statistics for Variable: Number of Pieces ..................................46

4.18 ANOVA Table for Number of Pieces ............................................................46

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LIST OF FIGURES

3.1 Display of distal vs. proximal end of deer femur .............................................14

3.2 Independent variables used in the present study ..............................................15

3.3 Removal of extra flesh from deer femora ........................................................16

3.4 Osteometric board and sliding caliper .............................................................17

3.5 Bones soaking on hot plates at less than 200 degrees Fahrenheit ....................18

3.6 Bones in warm water bath to loosen remaining tissue .....................................19

4.1 Right angles perpendicular to the bone shaft ...................................................23

4.2 Percentage of right angles by bone condition (within group) ..........................24

4.3 Acute angled bone ............................................................................................25

4.4 Percentage of acute angles by bone condition (within group) .........................26

4.5 Right angles .....................................................................................................27

4.6 Acute angles .....................................................................................................27

4.7 Example of jagged edged fracture ...................................................................28

4.8 Jagged edges by bone condition (within group) ..............................................29

4.9 Curved edge .....................................................................................................30

4.10 Percentage of curved edges by bone condition (within group) ......................31

4.11 Jagged edges ..................................................................................................32

4.12 Curved edges ..................................................................................................33

4.13 Rough edge morphology ................................................................................34

4.14 Rough edge morphology ................................................................................34

x

4.15 Percentage of rough surfaces by bone condition (within group) ...................35

4.16 Smooth Fracture Surface ................................................................................36

4.17 Percentage of smooth surfaces by bone condition (within group) .................37

4.18 Smooth surfaces .............................................................................................38

4.19 Rough surfaces ...............................................................................................39

4.20 Percentage of transverse fractures by bone condition (within group) ...........40

4.21 Transverse fractures .......................................................................................41

4.22 Radiating fracture line ....................................................................................43

4.23 Curved Radiating fracture line .......................................................................44

4.24 Radiating fracture lines ..................................................................................44

4.25 Radiating fracture lines ..................................................................................45

1

CHAPTER 1: INTRODUCTION

Interpersonal violence between and among individuals is a major problem in societies all

over the world today as well as in the past (Aufderheide et al., 1998). Bone breakage analysis is

one way to quantitatively examine a specific aspect of this widespread problem. In

bioarchaeology and in forensic work, there is a problem identifying perimortem from

postmortem breaks in long bones. Aside from the two extremes of green stick fractures in very

fresh bones and perfectly transverse breaks in dry bones, there is no set methodology to

categorize all of the breaks between the two extremes. Therefore, the question remains

unanswered as to whether or not there are specific criteria from which one can differentiate

between perimortem and postmortem breakage patterns in long bones.

Determining cause and manner of death is one of the top priorities in homicide

investigations. It is also important to the archaeologists who piece together human remains to

help reconstruct the individuals of past societies. In the much debated research on the practice of

cannibalism, bone fracture analysis has provided insight into perimortem fracture patterns. For

example, one site in Navatu, Fiji includes a “formal human burial site with a separate,

contemporaneous midden containing commingled fragmentary human and nonhuman bones”

(Degusta, 1999, p. 215) that are thought to have been butchered. An increase in knowledge about

bone fracture patterns may help to accurately determine the cause and manner of a person’s

death (Symes et al., 2005). The results of this study will be applicable to bioarchaeologists and

forensic scientists alike in determining the approximate time that the break took place. Sharp,

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irregular breaks are expected to be common in perimortem fractures because of the high moisture

content within the bone which absorbs and spreads out the stress of the trauma. A transverse

fracture is often seen on an “old” bone because of the lack of moisture in the bone (like a twig

breaking in half).

Actualistic research with human bones is limited by difficulties in obtaining large

samples for experiments that can be controlled and replicated. Fractured bones found in the field

could have been the result of trampling, animal gnawing, as well as natural events such as

landslides. Furthermore, the level of confidence and precision is increased in a controlled

laboratory setting (Villa and Mahieu, 1991). With this being the case, this study will use deer

femora which are easy to obtain in large quantities for a robust study sample.

The experimental study design included two experimental groups (old bones, n = 46; new

bones, n = 41). These groups were further divided, depending on which end of the bone was

analyzed (new distal, new proximal, old distal, old proximal). The purpose of this experiment

was to find out if certain fracture characteristics, such as smooth or rough fracture surfaces and

jagged or curved edges, appear more frequently in one group of bones than other groups.

Additionally, statistical tests were run to compare all groups. The study's 10 dependent variables

were measured and assigned values for the bone characteristics. Descriptive statistics,

correlational analyses, and analysis of variance tests were conducted. For all analyses, a two-

tailed, p = 0.05 alpha level was used to indicate statistical significance. A significant difference

between groups may help future researchers to categorize unknown bones as having either a

perimortem or a postmortem break.

The goals of this research are two-fold. The first is to determine if any variables appear in

one group of broken bones that do not occur in the other, supporting the idea that there is a

methodology to distinguish a perimortem break from a postmortem one. The second goal is to

3

establish a more reliable methodology for observing these fracture pattern differences that is

applicable to both the fields of forensic science and archaeology. For example, current methods

for analyzing bones found at a crime scene or archaeological site include taking bones back to a

laboratory for a series of complex analyses. These procedures risk labeling and cataloging

mistakes, breakage, and other errors that would compromise the integrity of the evidence or

artifacts. I hypothesize that perimortem fracture patterns in deer femora will contain more acute

angles and smooth edges at the break site than right angles, which are thought to be more

prevalent in postmortem breaks. By facilitating the identification of perimortem breaks from

postmortem ones, this study has the capacity to make an important contribution to law

enforcement and archaeological sciences.

Current studies of skeletal trauma provide clues that can be used to discover information

about the lives of these deceased individuals, in addition to providing insight into the lives of the

people of ancient populations (Walker, 2001). Archaeologists have explored bone modifications

found in human burial middens to look for evidence of foul play. The discovery of bite marks,

cut marks, and fragmentation have led to theories of dismemberment and cannibalism as

common cultural practices among some ancient groups of people (Degusta, 2000; Villa &

Mahieu, 1991; White, 1992). Because the distribution of missing osteological elements has been

found in some cases to be identical in formal burials as well as in assemblages where there is

clear evidence of traumatic and perimortem dismemberment, it is imperative to look closely at

the fracture surfaces. Studies have recreated bone modifications on bones with varied

perimortem intervals in order to gather more information about the fracture surface

characteristics in relation to the time since death (Blasco et al., 2008).

Specifically, evidence of bone trauma can shed light on interpersonal violence in the field

of forensic science, as well as warfare and other lifestyle behaviors in the archaeological record

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(Aufderheide et al., 1998). Traumatic injuries found in ancient human skeletal remains are one of

the only direct sources of evidence for scientific testing of theories (Walker, 2001). Through the

scientific method, theories of warfare and violence can be objectively tested and are not as

vulnerable to the interpretative difficulties posed by literature, such as historical records and

ethnographic reports. However, all forms of evidence are subject to interpretive difficulties. The

other goal of this experiment is to find a method to differentiate bone fracture patterns in relation

to when they occurred in the life of the deceased individual. Specifically, criteria from which one

can distinguish perimortem and postmortem breakage patterns in long bones are of paramount

importance to the advancement of forensic science and bioarchaeology today (Wheatley, 2008).

5

CHAPTER 2: LITERATURE REVIEW AND SIGNIFICANCE

The time around death or “perimortem interval” is important to forensic scientists

because it provides clues as to the cause and manner of a person’s death. It is known that bone

moisture content is strongly associated with fracture morphology (Wieberg and Wescott, 2008).

Bones begin losing moisture and their flexible collagen matrix at death; however, bones lose

moisture and flexibility slowly through decomposition, which complicates assessment of the

perimortem interval. A skeleton offers morphological clues that may aid scientists in determining

events that occurred in a person’s life. Functional implications for postural and locomotory

behavior and evidence for medical treatment were noted by Neri and Lancellotti (2004). An old

male skeleton found circa 1900 in good condition of preservation with known age, sex, and life-

activity is helpful in comparing an unknown skeleton (Neri and Lancellotti).

Wieberg and Wescott’s (2008) fracture study incorporated domestic pig (Sus scrofa)

bones in an effort to differentiate perimortem and postmortem fracture patterns. Fleshed ulnae,

femora, and tibia were fractured in groups of 10 every 28 days over a 141-day period. Their

results suggested an ambiguity in the perimortem interval definition that extended the full length

of the study.

Another issue to consider concerning perimortem and postmortem breakage patterns is

how to distinguish human induced fractures (such as cases involving foul play) from bones

modified by natural (biological and geological) agencies (Johnson, 1985). Villa and Mahieu

(1991) studied the breakage patterns of long bones to explore a cannibalism hypothesis. The site

where cannibalism was suspected had long bones with long and oblique fractures down the

6

diaphysis. These bones were found without the rest of the skeleton. In the two sites where

cannibalism is not suspected, the bones were found in situ with the rest of the skeleton; these

breaks were either incomplete or the bone was broken in half.

Villa and Mahieu (1991) investigated three assemblages in Southern France in an attempt

to distinguish intentional breakage of human bones. Features examined were fracture angle,

outline, and edge, as well as shaft circumference, fragmentation, and length. The first assemblage

of bones was broken by pressure and impact of sediment layers on subfossil bone. Incomplete

fracture lines indicated the long-term process acting on progressively weakened and dried bones.

All bones were in contact with their conjoinable counterparts from articulated skeletons or

articulated anatomical segments.

The second group comprised what are thought to be cannibalized fresh long bones that

were broken for extraction of marrow. In all, 156 shafts were studied that were buried 15 cm

deep (3930 ± 130B.C.), indicating that this area was not a formal burial site. Bone breakage by

percussion on green bone was evidenced by multiple factors, most notably that the bone surfaces

are unweathered, uneroded, and had sharp fracture edges. Fragments of the same bone were not

found adjacent to each other (separated by up to 50 cm). Bones found next to each other were

either superimposed or positioned head to tail. It is thought that these bones were broken prior to

being thrown into the pit. In addition, 10 other clusters containing butchered animal bones had

similar sharp horizontal and vertical fracture edges; however, no tooth marks indicating animal

gnawing were present. Cutmarks were found on 30% of bones created by stone tools. These

marks are not recent, because the small trowel marks found at the third site do not mimic those

of stone tools. The location of cutmarks on the bones were similar to those of modern butchery

and comparable to those found in faunal assemblages; the bones were found in pristine

7

condition. Cortical surfaces were found to be compact with dense texture and showed evidence

of one breakage cycle (intentional), displaying fresh, sharp edges (Villa and Mahieu, 1991).

The third site was a “collective burial with bones broken by the pick and shovel of the

land owner and amateur archaeologist” (Villa and Mahieu, 1991, p. 28). Bones were found in a

flat burial chamber. The color of the fracture surfaces indicated two cycles of breakage. The first

cycle indicated that either a roof collapsed on the burial chamber or sediment pressure impacted

the bones. The second cycle indicated haphazard and violent excavation methods were used;

these fracture surfaces were white. All species of bones were attributed to the genus Homo (Villa

and Mahieu). Results of this investigation led Villa and Mahieu to the conclusion that the latter

two sites contained bones broken by weathering and sediment layers, whereas the breaks found

at the first site were intentional and occurred during the perimortem interval suggesting the

possibility of cannibalism.

Essential to the study of bone fracture patterns is the understanding of bone as a material,

what physical properties are critical to its response as a material, and how its response is affected

by altering its physical properties. Bone microstructure governs bone failure and the resulting

fracture pattern. Fracture is a localized mechanical failure; therefore, microstructure properties

and mechanics must be acknowledged (Johnson, 1985).

Fresh green bone is bone that contains a high moisture content and fresh marrow in the

medullary cavity. Fresh marrow "greatly increases the ability to absorb stress" (Wheatley, 2008,

p. 1). In contrast to dry bone, fresh bone does not behave in a brittle or inflexible manner, but is

instead visoelastic (flowable and deformable) and ductile, capable of withstanding great amounts

of pressure and deformation before failure. Fresh long bones have a characteristic fracture

response to force known as spiral or curved fracture. A controversy exists in taphonomic and

8

bone research over how spiral or curved fracture patterns are induced in fresh bone (Johnson,

1985).

Mammalian bone is a highly complex, multiphased, heterogeneous, composite material

that is visoelastic and anisotropic (having contrasting mechanical properties that respond

differently to an external stimulus but when combined are stronger than either substance alone).

Anisotropic analysis and failure theories for both bone and inorganic composites are based on

stress (local force intensities) and strain (local deformation) in the principal axial direction. Long

bones typically consist of two tissue forms, that of cancellous bone at the epiphyseal ends and

compact bone at the diaphysis. At the microstructural level, cancellous bone consists of an open

network of plates and columns known as trabeculae. Compact bone is a composite of laminated

and haversian bone. It consists of several features such as osteons, interstitial lamellae, lacunae,

and Volkmann's and haversian canals (Johnson, 1985).

Haversian bone contains osteons that surround the haversian canals, which contain blood

vessels. These secondary osteons are oriented longitudinally with the axis of the whole bone and

consist of concentric lamellae of collagen fibers oriented preferentially (longitudinally). This

preferential orientation governs bone reaction when the bone is stressed. Stress is defined as the

local force intensities or internal or intermolecular resistance within a body to the deformation

action of an outside force. Strain is the local deformation or change in the linear dimensions of a

body as the result of an outside application of force (Johnson, 1985).

Moisture content is an important aspect of bone strength. Air dried bone fractures more

easily due to water loss that decreases its ability to absorb stress and increases in stiffness that

makes the bone less flexible. Dry bone, therefore, behaves more as an inorganic material and

becomes brittle. Wet bone behaves in a ductile manner, being able to withstand a large amount of

strain before failure. The presence of moisture in living bone greatly enhances its energy-

9

absorbing capacity. Also, because of the differences in structural properties of long bones, waves

of pressure are reflected and diffused in the epiphyses so that fresh bone fracture fronts do not

crosscut epiphyseal ends (Johnson, 1985).

Andrushko et al. (2005) noted trophy taking of enemies’ forearms during battle by

excavating a prehistoric archaeological site in central California. Holes were drilled through both

proximal and distal ends of the ulnae and radii. Interestingly for the current study, oblique

fractures were also found, indicating that the bone was broken around the time of death.

Researchers know this because the bone must have retained a high collagen content to allow for

this oddly shaped fracture. A dry bone would have been too brittle and would have either

shattered or broken off at a right angle. Another indicator of perimortem stress at the California

site is the cutmarks. Morphologically, they were similar in the human remains to the butchery

marks in other mammals commonly used as food. Other factors suggesting perimortem injury at

the site include the facts that no interior cortical bone shattering was observed and that the

interior color of the tool marks was the same as that of the remaining cortical surface (Andrushko

et al.) due to absorption of surrounding environmental pigmentation.

Niven (2007) discovered reindeer and horse bones, containing cut marks on upper long

bone shafts indicating meat removal (not disarticulation) possibly by early modern human groups

during the Pleistocene Aurignacian (31-32 ka.) This discovery was made at the Vogelherd Cave

site in Southwest Germany.

Researchers who excavated a site in Mangaia, in the Cook Islands, have argued that

environmental stressors caused the inhabitants to practice cannibalism between 1390 and 1470

A.D. (Steadman et al., 2000). The stratigraphic layer in question contains an earth oven filled

with human remains. The results of radiocarbon ([sup14]C) dating and accelerator-mass

spectrometer (AMS) analysis of the bones at this site correspond with sociopolitical stress and

10

ethnographic records complied by missionaries and colonial officials. The stressors listed are

high-density populations, highly intensified production systems, reduced natural resources,

hierarchical political control and social stratification, and intense competition for land and other

resources. The human remains found in this strata were disarticulated and browned, but not

calcified (such as in the case of cremation). The ethnographic records indicate that “groups or

individuals practiced opportunistic cannibalism of nutritive necessity" (Steadman et al., p. 878).

The bones represent people of all ages and both sexes. Bones found in the stratigraphic layers

both above and below, contained primarily bones of other animals, such as pigs, dogs, and fish

(Steadman et al.).

At the Richards site in the Ohio Valley area, human remains were found commingled

with other faunal remains (such as deer) in midden pits (Edgar and Sciulli, 2006). All remains

had the same man-made butcher marks on the bone, leading the researchers to speculate that both

humans and deer were prepared for human consumption (Edgar and Sciulli). This same

butchering pattern has been found from the remains of the Chaco Anasazi culture in the

American Southwest (Hurlbut, 2000). Altered human bones of all ages and both sexes have been

found in over thirty sites around the area. Bone modification includes fragmentation,

disarticulation, cut marks, percussion fracture, burning, and endpolishing (from boiling). The

human remains in these sites resemble those of previous sites listed in that they were found with

other faunal remains known to be used for human consumption with the same butchery patterns

(Hurlbut).

On the other hand, similar perimortem injuries have been found in archaeological sites of

the prehistoric Puebloan cultures of the American Southwest, but Darling (1999) argues that this

evidence does not necessarily indicate cannibalism. There was evidence of perimortem butcher

marks and burned bones, but the ethnographic data reveals that there was a mass execution of

11

witches (or people accused of witchcraft) during that period of time (Darling). Furthermore,

witches were associated with cannibalism, a practice that was repugnant to the Pueblo culture. It

is speculated that witches were dismembered to prevent any evil incarnations. It would not make

sense for this culture to practice the act of cannibalism, since it was considered taboo (Darling).

Criteria have been proposed to distinguish a human cremation site (as opposed to a

human “cooking” site). Because of the high heat required for cremation, the remaining bones

were calcified, warped, cracked and fractured. A true cremation site would contain no

perimortem fractures (unless the cultural standard dictated secondary burial in pots), such as

butcher marks or longitudinal and oblique breaks (Whyte, 2001).

Another use for modifying fresh bone is tool production. Awls and projectile points

produced from bone have been found at the Blombos Cave in Africa. The oldest tools are dated

to the Middle Stone Age (about 70,000 years ago), but most bone tools have been found in

Europe after 40,000 years ago (Henshilwood et al., 2001).

Significant differences have been found between some fracture pattern characteristics; for

example, wet (new or green) bones (postmortem interval < 4 days) have more smooth surfaces

and fracture lines radiating out from the site of trauma, whereas dry (old) bones (postmortem

interval > 2 months) have rougher edges around the site (Wheatley, 2008). These differences

were more likely to be found on the proximal surface of the fracture (bones were held in a vice

by the femoral head). The significant differences found between perimortem and postmortem

samples were on the proximal side of the break. In the current study, the bone was held in a vice

on the distal end. This variation on the previous research may allow researchers to determine

whether or not the differences found are true differences between the two bone groups (old vs.

new), or design-dependent differences.

12

Bone weathering has revealed that femora resist outside elements better than other bones,

such as metatarsals (Janjua and Rogers, 2008). Temperature, humidity, sunlight, and

precipitation were all taken into account. The “microenvironment,” such as soil composition,

was taken into account as well. The rate of decomposition was noted over a set of specific time

periods (Janjua and Rodgers). Although this study is not specifically applicable to the current

study, it will be a valuable resource when accounting for environmental variables applicable to

the study.

Fracture shape is arguably the best indicator for exemplifying perimortem trauma (Symes

et al., 2005). Using microscopic analysis, a smooth, shearing fracture pattern can be seen in these

cases. This pattern is not usually seen in postmortem fractures. A continuous fracture line that

traverses the entire break is indicative of a postmortem injury. These fracture lines are also able

to be seen with the naked eye through the use of back-lighting (Symes et al.).

Even though the evidence supporting microscopic analysis is an important contribution to

the scientific community, one of the goals of this experiment is to discover these differences in

fracture patterns macroscopically. The reason for this design is so that a more convenient

methodology can be established and used in more practical situations. Using a methodology

where no equipment is necessary, forensic scientists and archaeologists alike can make

preliminary guesses as to the nature of the fracture while in the field at an archaeological site or

at a forensic crime scene.

Due to the results of previous research on the decomposition rates of different bone

samples (Johnson, 1985; Wheatley, 2008; Wieberg and Wescott, 2008), this experiment will use

a specific bone (deer femora) known to be robust and resistant to environmental variables that

could possibly affect the validity of the results. While femora is robust in both deer and humans,

there is a morphological difference. Deer femora, Odocoileus virginianus, "has both plexiform

13

and haversian bone tissue, whereas, plexiform bone may only be present in human fetal or

pathological bone" (Wheatley, 2008, p. 1).

Despite the advances in research over the years in both the fields of forensic science and

archaeology concerning this specific problem, the results are largely inconclusive for a variety of

reasons. Currently, it is still extremely difficult to determine if any fracture characteristics appear

in a group of bones broken around the time of death that do not occur in an older group of bones

(and vice versa) because of large variations in the perimortem interval. More research is needed

to identify methods for distinguishing a perimortem break from a postmortem break. This

methodology will need to be replicable in many different and diverse settings and will need to

establish a more reliable methodology to use in observing fracture pattern differences.

The study hypothesis is that perimortem fracture patterns in deer femora will contain

more acute angles and smooth edges at the break site than right angles, which are thought to be

more prevalent in postmortem breaks. The acute and smooth edged breaks are common in

perimortem fractures because of the high moisture content within the bone, which absorbs and

spreads out the stress of the trauma. In addition, a transverse (or right-angled) fracture is often

seen on a postmortem bone because of the lack of moisture in the bone (like a twig breaking in

half). In the current study I analyzed these bone characteristics, and others, through statistical

tests in an attempt to establish a more convenient methodology for identifying bone fracture

characteristics, as previously discussed.

14

CHAPTER 3: METHODS

The design of the present study is an experimental design with two experimental groups

(postmortem; n = 46; perimortem; n = 41). Details about the study population and the

experimental groups are provided in this chapter. The study design includes two independent

variables; the first is the condition of the bone (perimortem vs. postmortem), which refers to the

amount of time that elapsed between the death of the deer and the breaking of the femur.

Perimortem status means that the bones were broken less than two days after the death of the

deer. Postmortem status means the bones were broken at least sixty days after the death of the

deer. The second independent variable is the end of the bone that contains the fracture surface

(proximal vs. distal). The proximal end of the bone contains the femoral head and the distal end

is closer to the knee (Figure 3.1).

Figure 3.1. Display of distal vs. proximal end of deer femur.

Distal ProximalDistal Proximal

15

The significance of this variable relates to the position of the bone during breakage.

Bones were held in a vice on the distal end during breakage while the proximal end rested on a

foam pad. I wanted to determine if results (fracture patterns) could be attributed to bone end

stabilization (distal) vs. bone condition (old vs. new), alone. A diagram showing the study

independent variables is provided in Figure 3.2.

Figure 3.2. Independent variables used in the present study.

Description of Study Sample

Shortly before the end of deer-hunting season in January 2008, a research group

consisting of graduate and undergraduate students at the University of Alabama at Birmingham

gathered and processed bones used in the study. A sample of white-tailed deer (Odocoileus

virginianus) was obtained from two game-processing facilities near Birmingham, Alabama. One

group of deer femora (old) was left outdoors and uncovered on a nearby property to naturally dry

for a period of two months. The other group (new) was taken directly to a plot of land

approximately 20 foot X 30 foot, surrounded by a wooden fence, where the remaining tibiae and

soft tissue were removed from most of the femora; the remaining bones from the new group were

defleshed with scalpels and scissors the day of the experiment (Figure 3.3).

16

Figure 3.3. Removal of extra flesh from deer femora.

Research Design and Procedures

This study's experimental design consisted of two experimental groups (postmortem; n =

46; perimortem = new; n = 41). All femora were scored on a variety of characteristics (Degusta,

2000; Wheatley, 2008) that comprised the dependent variables. The following were used as

dependent variables: the presence or absence of (a) right angled fractures, (b) acute angled

fractures, (c) jagged edges along the fracture surface, (d) curved edges, (e) smooth bone surface

along the fracture line, (f) rough bone surface along the fracture surface, (g) transverse fractures,

(h) butterfly fractures, (i) the number of fracture lines, and (j) the number of pieces created

during the breaking of the bone. The independent variables were (a) the condition of the bone

(old, new) and (b) the end of the bone (proximal, distal; Wheatley, 2008). From the total number

of bones in the new group that were collected (n > 50), only 41 of the new bones broke on

impact; therefore, these 41 bones comprised the sample of new (perimortem) bones used in the

study. From the total number of bones in the old group that were collected (n > 50), only 46 of

17

the old bones broke on impact; therefore, these 46 bones comprised the sample of old

(postmortem) bones used in the study.

The bones used for analysis were taken to the bioengineering lab at The University of

Alabama-Birmingham (UAB) to conduct the experiment. New bones were tested within 2 days

of receipt and old bones were tested at least 60 days following receipt from the deer processing

facilities. In order to ensure and maintain a level of consistency, the same people, techniques,

and instruments were used to provide measurements of the bones. Two instruments were used

for bone measurements: an osteometric board and a sliding caliper. The osteometric board was

used to measure the length of long bones. The sliding caliper was used to measure smaller

increments, such as the anterior and posterior width, as well as lateral width of the deer femora.

All readings were recorded in millimeters. After the measurement was recorded, the bone was

assigned a case number and placed inside a plastic re-sealable bag (Figure 3.4).

Figure 3.4. Osteometric board and sliding caliper.

18

The deer femora were fractured using a Dynatup 8250 Drop Weight Impact Test Machine

(DWITM), which applied approximately 13.63 kg of concentrated and sudden compressive force

to the anterior surface of the mid-shaft of each bone. The striking surface of the drop weight

where it impacted the bone measured 3 in. x 4 in.2. The distal femur ends were secured in a vice.

The proximal ends were placed on a foam pad in an effort to generate a shearing force to cause a

natural fracture pattern.

After each impact, the femur fragments for each bone were gathered and returned to the

bone's numbered re-sealable bag. Each bag was then taken to the processing laboratory, where a

1:1 ratio of baking powder and enzymatic-action detergent was added to water and poured over

the bone fragments in their respective bags. Heat no greater than 200ºF was introduced in two-

hour increments. The heat loosened any remaining soft tissue on the bone and the marrow that

was left inside the bone (Figures 3.5 and 3.6).

Figure 3.5. Bones soaking on hot plates at less than 200ºF.

19

Figure 3.6. Bones in warm water bath to loosen remaining tissue.

The enzymatic-action detergent breaks up the residual oils in and around the bones. By

heating the bones at a temperature of less than 200ºF, the fracture surface retains the integrity of

its shape. Heating bones at higher temperatures than this may cause the structure of the bone to

break down. After each two-hour increment, the bones were removed from the heat and bits of

organic material removed. After three consecutive detergent baths, the bones were given a final

cleaning and placed in a diluted ammonia bath for another 2 hr. Any remaining oils or fats from

the specimens were extracted by the ammonia solution (Fenton, 2007). Bones were then rinsed

and placed under a fume hood to dry.

Tests and Measurements

All 10 of the dependent variables were measured and assigned values along the

fracture surface. Information about the dependent variables is provided in Appendix D. The

operational definitions for the dependent variables follow:

20

1. Right Angle: Does the bone have a right-angled fracture that encompasses at least 25%

of the fracture surface? (The remaining 75% of the fracture surface may reveal other features,

such as an acute angle on the same fracture surface as the right angle.)

2. Acute Angle: Does the bone have an acute-angled fracture that encompasses at least

25% of the fracture surface?

3. Jagged Edge: Does the bone have a jagged edge along the fracture surface that

encompasses at least 25% of the circumference?

4. Curved Edge: Does the bone have a curved edge that encompasses at least 25% of the

fracture surface? (Spiral fractures were classified as curved edges.)

5. Smooth Surface: Does the bone have a smooth surface that encompasses at least 25%

of the fracture surface?

6. Rough Surface: Does the bone have a rough edge that encompasses at least 25% of the

fracture surface?

7. Transverse Fracture: Does the bone have a transverse fracture along the Z-axis on at

least 75% of the circumference? A transverse fracture crosses the diaphysis at right angles to the

long axis of the bone (Byers, 2008).

8. Butterfly Fracture: Does the bone contain a butterfly fracture? (A butterfly fracture is a

bilateral winged-shaped fracture that occurs around the site of impact on the diaphysis; Byers,

2008).

9. Fracture Lines: How many fracture lines does the bone have?

10. Number of Pieces: Into how many pieces did the bone break?

Descriptive statistics, correlational analyses, and analysis of variance tests were

conducted. For all analyses, a two-tailed, p = .05 alpha level was used to indicate statistical

significance. All statistics were calculated using SPSS 15.0 (SPSS Inc., Chicago, IL).

21

Chapter 4: Results

Bones used in the study were examined on 10 dependent variables. Bones were

categorized as old/dry (postmortem) or as new/wet (perimortem) and were further classified

depending on the bone end (proximal, distal) measured. The angles along the fracture line of the

bones were then also measured to specifically look for right and acute angles. The presence or

absence of smooth and rough edges along the Y and Z -axes of the bone was recorded. I noted

the transverse fractures along the Z-axis, as well as jagged edges, curved edges, and butterfly

fractures. I also measured the number of pieces into which the bone broke and the number of

radiating fracture lines from the break site. I observed the bones without a microscope, so that

the methodology could be used and applied to samples in the field, as opposed to transporting the

samples back to a laboratory. To analyze the data, values were assigned to the variables and

entered the data into a statistical program. All statistics were calculated using SPSS 15.0 (SPSS

Inc., Chicago, IL). I then noted the results and their respective levels of significance.

Statistical tests used an alpha level of .05 for significance. A one-way multivariate

analysis of variance (MANOVA) was performed, examining the effects of the independent

variables (IVs) bone condition (old, new) and bone end observed (proximal, distal) on breakage

patterns (DVs) when breaking deer femora with a drop-weight impact machine. Using the

dependent variables as dichotomous data (0, 1) in analysis of variance calculations is supported

in the literature (Lunney, 2005) and was performed in order to compare all categories of

variables. Spearman's rho (similar to Pearson's r used for parametric data) is a nonparametric

22

procedure used to examine the correlation between two variables that are at least ordinal data.

Normal distribution is not needed. (Bone condition and number of occurrences of fracture

patterns were deemed at least ordinal data). The following patterns were analyzed: angles (right

and acute), edges (jagged and curved), surfaces (smooth and rough), transverse fractures,

butterfly fractures, number of fractures lines, and number of pieces created by the break (Table

4.1).

Table 4.1: Descriptive Statistics for Variables for Bone Characteristics

Variable f % of total Right angles Old 59 33.9 New 15 8.6 Acute angles Old 57 32.8 New 79 45.4 Jagged edges Old 64 36.8 New 55 31.6 Curved edges Old 76 43.7 New 70 40.2 Smooth surface Old 17 9.8 New 45 25.9 Rough surface Old 85 48.9 New 46 26.4 Transverse fracture Old 14 8.0 New 12 6.9 Butterfly fracture Old 9 10.3 New 6 6.9

Right angles were present in 33.9% of cases in the postmortem group and 8.6% in the

perimortem group. A Spearman rho correlation coefficient was calculated for the relationship

between the bone condition and right angles (Cronk, 2008). A negative correlation was found

(rho = -.463, p < .001) indicating a significant relationship between the two variables. In this

experiment, old bones tend to exhibit a right angle fracture surface. Note the morphological

23

characteristics in a postmortem bone (Figure 4.1), especially how the fracture surface along the

shaft forms a right angle across the top of the figure.

Figure 4.1. Right angles perpendicular to the bone shaft.

Table 4.2 contains information about the frequency of occurrence and absence of right

angles and their respective percentages. Figure 4.2 displays this data graphically. Table 4.4 and

Figure 4.5 contain results of statistical analyses for right angles.

Table 4.2: Frequency and Percentage of Right Angles

Variable f % within right

angles Right angles present Old proximal 31 41.9 New proximal 3 4.1 Old distal 28 37.8 New distal 12 16.2 Right angles absent Old proximal 30 15.0 New proximal 41 38.0 Old distal 27 18.0 New distal 38 29.0

24

Figure 4.2. Percentage of right angles by bone condition (within group).

Acute angles were present in 32.7% of cases in the postmortem group and 45.4% in the


between the bone condition and acute angles. A positive correlation was found (rho = .415, p <

.001) indicating a significant relationship between the two variables. In this experiment, new

bones tend to exhibit an acute angle fracture surface. Note the morphological characteristics in a

perimortem bone (Figure 4.3), especially how the fracture surface along the shaft dips inward

making a pointy edge with the outside surface, and forming an acute angle rather than a right

angle.

25

Figure 4.3. Acute angled bone.

Table 4.3 contains information about the frequency of occurrence and absence of acute

angles and their respective percentages. Figure 4.4 displays this data graphically. Figure 4.6 and

Table 4.4 contain results of statistical analyses for acute angles.

Table 4.3: Frequency and Percentage of Acute Angles

Variable f % within acute

angles Acute angles present Old proximal 30 22.1 New proximal 41 30.1 Old distal 27 19.9 New distal 38 27.9 Acute angles absent Old proximal 16 42.1 New proximal 0 0.0 Old distal 19 50.0 New distal 3 7.9

26

Figure 4.4. Percentage of acute angles by bone condition (within group). A one-way MANOVA was calculated examining the effect of breaking deer femora with

a drop-weight impact machine on fracture angles (right, acute). The analysis was significant (F =

9.270, df = 6, p < .001). As shown in Table 4.4, Pillai’s Trace value (p < .001) indicates the

significance in the multivariate model. A significant difference was found for right angles (F =

17.868, df = 3, p < .001) and for acute angles (F = 12.404, df = 3, p < .001) depending on bone

condition (old proximal, old distal, new proximal, new distal). Figures 4.5 and 4.6 are provided

to describe the relationships between the fracture angles (right, acute) and bone condition.

27

Figure 4.5. Right angles

Figure 4.6. Acute angles

28

Table 4.4: MANOVA Table for Right and Acute Angles

Effect Source F df Significance Partial Eta squared Right angles Pillai's Trace 17.868 3 < .001 .240 Acute angles Pillai's Trace 12.404 3 < .001 .180

Jagged fracture outlines were frequent and almost evenly distributed between old and

new groups (36.8%, 31.6%). A Spearman rho correlation coefficient was calculated for the

relationship between the bone condition and jagged edges. A correlation was not found (rho = -

.027, p = .726) indicating no significant relationship between the two variables. In this

experiment, old and new bones tend to exhibit a jagged fracture surface at similar rates. Figure

4.7 displays a jagged fracture surface.

Figure 4.7. Example of jagged edged fracture.

29

Table 4.5 contains information about the frequency of occurrence and absence of jagged

edges and their respective percentages. Figure 4.8 displays this data graphically. Figure 4.11 and

Table 4.7 contain results of statistical analyses for jagged edges.

Table 4.5: Frequency and Percentages of Jagged Edges

Variable f % within

jagged edges Jagged edges present Old proximal 28 23.5 New proximal 25 21.0 Old distal 36 30.3 New distal 30 25.2 Jagged edges absent Old proximal 18 32.7 New proximal 16 29.1 Old distal 10 18.2 New distal 11 20.0

Figure 4.8. Percentage of jagged edges by bone condition (within group).

30

Curved edges were present in 43.7% of cases in the postmortem group and 40.2% in the


between the bone condition and curved edges. A correlation was not found (rho = .037, p = .624)

indicating no significant relationship between the two variables. In this experiment, old and new

bones tended to exhibit a curved edge at similar rates. Note the morphological characteristics in

the bone in Figure 4.9, illustrating a curved edge.

Figure 4.9. Curved edge.

Table 4.6 contains information about the frequency of occurrence and absence of curved

edges and their respective percentages. Figure 4.10 displays this data graphically. Figure 4.12

and Table 4.7 contain results of statistical analyses for curved edges.

31

Table 4.6: Frequency and Percentage of Curved Edges

Variable f % within

curved edges Curved edges present Old proximal 43 29.5 New proximal 40 27.4 Old distal 33 22.6 New distal 30 20.5 Curved edges absent Old proximal 3 10.7 New proximal 1 3.6 Old distal 13 46.4 New distal 11 39.3

Figure 4.10. Percentage of curved edges by bone condition (within group).

A one-way MANOVA was calculated examining the effect of breaking deer femora with

a drop-weight impact machine on fracture edges (jagged, curved). The analysis was significant

(F = 3.404, df = 6, p = .003). As shown in Table 4.7, Pillai’s Trace value (p < .001) indicates the

32

significance in the multivariate model. A significant difference was not found for jagged edges

(F = 1.591, df = 3, p = .193) depending on bone condition (old proximal, old distal, new

proximal, new distal); however, for curved edges, a significant difference was found (F = 6.267,

df = 3, p < .001). Figures 4.11 and 4.12 are provided to describe the relationships between the

fracture edges (jagged, curved) and bone condition.

Figure 4.11. Jagged edges.

33

Figure 4.12. Curved edges.

Table 4.7: MANOVA Table for Jagged and Curved Edges

Effect Source F df Significance Partial Eta squared Jagged edges Pillai's Trace 1.591 3 .193 .027 Curved edges Pillai's Trace 6.267 3 < .001 .100

Rough edges were present in 64.9% of cases in the postmortem group and 35.1% in the


between the bone condition and rough edges. A negative correlation was found (rho = -.420, p <

.001) indicating a significant relationship between the two variables. In this experiment, old

bones tend to exhibit rough surfaces around the circumference. Note the morphological

characteristics in two postmortem bones (Figures 4.13 and 4.14), illustrating rough surfaces. If

you were to run your finger around the edges pictured in Figures 4.13 and 4.14, they would feel

rough.

34

Figure 4.13. Rough edge morphology.

Figure 4.14. Rough edge morphology.

Table 4.8 contains information about the frequency of occurrence and absence of rough

surfaces their respective percentages. Figure 4.15 displays this data graphically. Figure 4.18 and

Table 4.10 contain results of statistical analyses for rough surfaces.

35

Table 4.8: Frequency and Percentage of Rough Surfaces

Variable f % within

curved angles Rough surface present Old proximal 41 31.3 New proximal 13 9.9 Old distal 44 33.6 New distal 33 25.2 Rough surface absent Old proximal 5 11.6 New proximal 28 65.1 Old distal 2 4.7 New distal 8 18.6

Figure 4.15: Percentage of rough surfaces by bone condition (within group).

36

Smooth surfaces were present in 9.8% of cases in the postmortem group and 25.9% in the


between the bone condition and smooth surfaces. A positive correlation was found (rho = .379, p

< .001) indicating a significant relationship between the two variables. In this experiment, new

bones tend to exhibit a smooth fracture surface. Note the morphological characteristics in a

perimortem bone (Figure 4.16) illustrating a smooth fracture surface.

Figure 4.16

Table 4.9 contains information about the frequency of occurrence and absence of smooth

surfaces and their respective percentages. Figure 4.17 displays this data graphically. Figure 4.19

and Table 4.10 contain results of statistical analyses for smooth surfaces.

37

Table 4.9: Frequency and Percentage of Smooth Surfaces

Variable f % within

smooth surfaces Smooth surface present Old proximal 14 22.6 New proximal 34 54.8 Old distal 3 4.8 New distal 11 17.7 Smooth surface absent Old proximal 32 28.6 New proximal 7 6.2 Old distal 43 38.4 New distal 30 26.8

Figure 4.17. Percentage of smooth surfaces by bone condition (within group).

A one-way MANOVA was calculated examining the effect of breaking deer femora with

a drop-weight impact machine on fracture surfaces (smooth, rough). The analysis was significant

(F = 14.682, df = 6, p < .001). As shown in Table 4.10, Pillai’s Trace value (p < .001) indicates

38

the significance in the multivariate model. A significant difference was found for smooth

surfaces (F = 29.004, df = 3, p < .001) and for rough surfaces (F = 27.925, df = 3, p < .001)

depending on bone condition (old proximal, old distal, new proximal, new distal). Figures 4.18

and 4.19 are provided to describe the relationships between the fracture surfaces (smooth, rough)

and bone condition.

Figure 4.18. Smooth surfaces.

39

Figure 4.19. Rough surfaces.

Table 4.10: MANOVA Table for Smooth and Rough Surfaces

Effect Source F df Significance Partial Eta squared Smooth surfaces Pillai's Trace 29.004 3 < .001 .339 Rough surfaces Pillai's Trace 27.925 3 < .001 .330

Transverse fractures were present in 8.0% of cases in the postmortem group and 6.9% in

the perimortem group. A Spearman rho correlation coefficient was calculated for the relationship

between the bone condition and acute angles. A correlation was not found (rho = -.008, p = .915)

indicating no significant relationship between the two variables. In this experiment, new and old

bones tend to exhibit transverse fractures at a similar rate. An image of a transverse fracture was

not available for inclusion.

40

Table 4.11 contains information about the frequency of occurrence and absence of

transverse fractures and their respective percentages. Figure 4.20 displays this data graphically.

Figure 4.21 and Table 4.12 contain results of statistical analyses for transverse fractures.

Table 4.11: Frequency and Percentages of Transverse Fractures

Variable f

% within transverse fractures

Transverse fracture present Old proximal 2 7.7 New proximal 2 7.7 Old distal 12 46.2 New distal 10 38.5 Transverse fracture absent Old proximal 44 29.7 New proximal 39 26.4 Old distal 34 23.0 New distal 31 20.9

Figure 4.20. Percentage of transverse fractures by bone condition (within group).

41

A one-way ANOVA was calculated examining the effect of breaking deer femora with a

drop-weight impact machine on transverse fractures. A significant difference was found for

transverse fractures (F = 5.231, df = 3, p = .002) depending on bone condition (old proximal, old

distal, new proximal, new distal). Figure 4.21 is provided to describe the relationships between

the transverse fractures and bone condition.

Figure 4.21. Transverse fractures

Table 4.12: ANOVA Table for Transverse Fractures

Effect Source F df Significance Partial Eta squared Transverse fractures Linear 5.231 3 .002 .085

Butterfly fractures were present in 10.3% of cases in the postmortem group and 6.9% in

the perimortem group. A Spearman rho correlation coefficient was calculated for the relationship

42

between the bone condition and butterfly fractures. A correlation was not found (rho = -.065, p =

.549) indicating no significant relationship between the two variables. In this experiment, new

and old bones tend to exhibit butterfly fractures at a similar rate. An image of a butterfly fracture

was not available for inclusion.

Table 4.13 contains information about the frequency of occurrence and absence of

butterfly fractures and their respective percentages. Table 4.14 contains results of statistical

analyses for butterfly fractures.

Table 4.13: Frequencies and Percentages of Butterfly Fractures

Variable f

% within butterfly fractures

Butterfly fracture present Old 9 19.6 New 6 14.6 Butterfly fracture absent Old

New 37 35

80.4 85.4


drop-weight impact machine on creating a butterfly fracture. A significant difference was not

found for creating a butterfly fracture (F = .362, df = 1, p = .549) depending on bone condition

(old, new). Table 4.14 displays the ANOVA statistics for butterfly fractures.

Table 4.14: ANOVA Table for Butterfly Fractures

Effect Source F df Significance Partial Eta squared Butterfly fractures Linear .362 1 .549 .004

43

Descriptive statistics for the number of radiating fracture lines present in each group is

provided in Table 4.15. A Spearman rho correlation coefficient was calculated for the

relationship between the bone condition (old, new) and number of radiating fracture lines. A

correlation was not found (rho = .089, p = .245) indicating no significant relationship between

the two variables. New and old bones tend to exhibit radiating fracture lines at a similar rate.

Figures 4.22 through 4.24 display examples of radiating fractures. Table 4.15 and Figure 4.25

contain statistical information about radiating fracture lines.

Figure 4.22. Radiating fracture line.

44



Table 4.15: Descriptive Statistics for Variable: Radiating Fracture Lines

Variable n M SD Radiating fracture lines Old proximal 46 .98 1.145 New proximal 41 1.34 1.389 Old distal 41 2.61 1.693 New distal 46 2.88 1.860

45


drop-weight impact machine on number of radiating fracture lines. A significant difference was

found for radiating fracture lines (F = 15.991, df = 3, p < .001) depending on bone condition (old

proximal, old distal, new proximal, new distal). Figure 4.25 is provided to describe the

relationships between the radiating fracture lines and bone condition. Table 4.16 provides

ANOVA statistics for radiating fracture lines.

Figure 4.25. Radiating fracture lines.

Table 4.16 ANOVA Table for Radiating Fracture Lines

Effect Source F df Significance Partial Eta squared Radiating fractures Linear 15.991 3 < .001 .220

46

Descriptive statistics for the number of pieces resulting from the break are provided in

Table 4.17. The number of pieces ranged from 2 to 14 for the old group (n = 46, M = 5.85; SD =

2.82), and 2 to 20 for the new group (n = 41, M = 6.98, SD = 4.76). The means of the two groups

were similar; however, the standard deviation for the perimortem group was higher than that of

the postmortem group (4.76 and 2.82 respectively). A Spearman rho correlation coefficient was

calculated for the relationship between the bone condition (old, new) and number of pieces. A

correlation was not found (rho = .062, p = .570) indicating no significant relationship between

the two variables. New and old bones tend to exhibit similar numbers of pieces. Tables 4.17 and

4.18 contain statistical information about number of pieces.

Table 4.17: Descriptive Statistics for Variable: Number of Pieces

Variable n M SD Number of pieces Old 46 5.85 2.820 New 41 6.98 4.757


drop-weight impact machine on number of pieces resulting from impact. A significant difference

was not found for number of pieces (F = 1.856, df = 1, p = .177) depending on bone condition

(old, new).

Table 4.18: ANOVA Table for Number of Pieces

Effect Source F df Significance Partial Eta squared Number of pieces Linear 1.856 1 .177 .021

48

Chapter 5: Discussion

This chapter discusses the interpretations of the study results and how they relate to my

original hypothesis and study goals. I hypothesized that perimortem fracture patterns in deer

femora would contain more acute angles and smooth surfaces at the break site than right angles

and rough surfaces and, conversely, that postmortem fractures would contain more right angles

and rough surfaces at the break site than acute angles and smooth surfaces. The goals of this

research were two-fold. The first was to determine if a methodology could be developed to

distinguish a postmortem bone fracture from a perimortem bone fracture. The second goal was to

establish a more reliable methodology for observing these fracture pattern differences that could

be applicable to both the fields of forensic science and archaeology.

For the variable of right angles, I found highly significant correlations between right

angles and the postmortem group. No differences were seen between proximal and distal ends

with regard to right angles. This indicates that the results (more right angles in the postmortem

group) were due to the actual condition of the bone, and not to the study design (i.e. which end of

the bone was held stationary). It is known from previous research (Johnson, 1985; Villa and

Mahieu, 1991; Wheatley, 2008; Wieberg and Wescott, 2008) that right angles are more prevalent

when very old and dry bones are fractured. The results of the current study support previous

findings, and demonstrate that this postmortem trait can be seen as early as 60 days after death.

Likewise, similar results were found in the variable of acute angles. A highly significant

correlation was found between acute angles and the perimortem group. Acute angles are more

likely to be found in new bones. No differences were seen between proximal and distal ends with

49

regard to acute angles. This result is also supported by the literature discussed in Chapter 2;

specifically, that acute angles are more prevalent when the fracture occurs around the time of

death (Villa and Mahieu, 1991; Wieberg and Wescott, 2008).

For the variable of jagged edges, no significant correlations were found between jagged

edges and the perimortem or the postmortem groups. No significant differences were found

between proximal and distal ends. Jagged edges have been found to be a postmortem trait in

previous research; however, results are dependent on the definition of jagged edges (Johnson,

1985; Villa and Mahieu, 1991). I classified a bone as having a jagged edge if it existed on 25%

of the fracture surface. This means that a bone from the perimortem group could have mostly

curves and smooth surfaces, but also have jagged edges around one 90 degree arc. If I changed

my criteria to 75%, I may have obtained results that agreed with the literature that supports

jagged edges as a postmortem trait (Johnson, 1985; Villa and Mahieu, 1991).

No significant correlations were identified between curved edges and the perimortem or

the postmortem groups. Interestingly, there was a significant difference found between proximal

and distal ends, regardless of bone age. Curved edges were almost always found on the proximal

side of the surface fracture. In the experiment, the proximal side was not secured when impacted

while the distal end was held stationary. This may have important implications when analyzing

the manner of how a bone was broken. With further study, this characteristic may give

researchers insight into the spatial orientation of the bone when broken, and possibly the

surrounding traumatic event.

Concerning the variable of smooth surfaces, a highly significant correlation was found

between smooth surfaces and the perimortem group. Further analysis with MANOVA indicated

that there was a highly significant difference between proximal perimortem and proximal

postmortem bones and between proximal perimortem and distal perimortem bones. Previous

50

research has shown that smooth surfaces are found to be a perimortem trait in general; however,

the findings of the present study lead me to speculate that there is some interaction taking place

among the variables.

A highly significant correlation was found between rough surfaces and the postmortem

group. Further analysis with MANOVA indicated a highly significant difference between

proximal perimortem and proximal postmortem bones and between proximal perimortem and

distal perimortem bones. Furthermore, MANOVA results indicated a significant difference

between proximal and distal bones regardless of bone condition (old, new). This leads me to

further speculate that interactions exist among variables, suggesting the necessity for further

research. While Wheatley (2008) found significant correlations between bone condition (old,

new) on both ends (proximal, distal), the different study designs preclude direct comparison of

statistical results.

No significant correlations were found between transverse fractures and bone condition

(old, new); however, further analysis with ANOVA indicated a significant difference between

proximal postmortem and distal postmortem bones. Since transverse fractures are widely

considered to be a postmortem trait (Wheatley, 2008; Wieberg and Wescott, 2008), especially in

very old bones, it makes sense that they would be found more often in the postmortem group.

However, since transverse fractures were found more often on the distal fracture surface of the

postmortem bones, this leads me to speculate that the difference is due to the design. The distal

end of the bones were held stable; therefore, less impact force could be absorbed and dissipated,

especially in postmortem bones, which have less moisture and elasticity. This finding supports

the theory that the perimortem interval is variable (Johnson, 1985; Wheatley, 2008; Wieberg and

Wescott, 2008).

51

No correlation was found between the number of radiating fracture lines and bone

condition (old, new). Results of ANOVA indicated a significant difference between proximal

and distal bone ends regardless of bone condition (old, new). The distal ends of bones in both

groups (old, new) had the same range (0-7) with respect to number of radiating fracture lines,

and the proximal ends of bones in both groups had similar ranges (0-5 and 0-4 respectively).

This leads me to speculate that radiating fracture lines are less a function of bone condition, and

more a function of study design. Since the distal end of each bone was held stable, the impact

force could not dissipate, causing the bone to fail more often on the distal end than on the

proximal end.

The number of pieces created from the break was not found to be significantly correlated

with bone condition (old, new). Interestingly, the standard deviation in the perimortem group

was 4.76 compared to 2.82 for the postmortem group. This means that perimortem bones are

highly variable with regard to number of pieces created by fracture trauma. New bones contain

more moisture, collagen matrix and bone marrow, which contribute to a more variable break. I

think this would be an intriguing avenue for further research.

Additional variables, such as fusion vs. nonfusion (Wheatley, 2008) might provide

additional information that would help to differentiate bone age. Wheatley used epiphyseal

fusion as a layer-effect variable in his fracture study. Epiphyseal fragments have not been

considered in the present study because epiphyses break differently from diaphyses, and this

study focused only on fracture patterns occurring on the diaphysis of the bone (Villa and Mahieu,

1991). Additionally, the availability of epiphyseal fragments is often restricted due to carnivore

activity. Carnivore-generated features are characterized by the presence of shafts or shaft

segments without their epiphyses (Villa and Mahieu). White (1992) found that femoral shafts are

over-represented relative to the epiphyseal ends at the Mancos study site.

52

Limitations of the present study included that data was gathered through visual

discrimination, which is subjective. The possibility of intra-observer error exists. Another

limitation of the study was that statistical analyses did not factor in size or chronological age of

the bone.

In summary, the study hypothesis was retained and the goals of the study were met.

Perimortem fracture patterns in deer femora did contain more acute angles and smooth surfaces

at the break site than right angles and rough surfaces; conversely, postmortem fractures

contained more right angles and rough surfaces at the break site than acute angles and smooth

surfaces. Based on study results, I believe a methodology could be developed to distinguish a

postmortem bone fracture from a perimortem bone fracture; however, other data would be

needed to triangulate with bone fracture patterns to make a definite determination.

53

CHAPTER 6: CONCLUSIONS

The present study explored some of the factors that may help scientists to accurately

classify a bone fracture as perimortem or postmortem. This research is important to

archaeologists who excavate sites containing osteological remains and to forensic scientists who

investigate crime scenes. Accurately deciphering when a break took place with respect to the

perimortem interval is important because this information can provide clues about interpersonal

violence, animal activity, or breakage that occurred simply due to sediment pressure. Living

bone has high moisture and collagen content; these characteristics begin to slowly decline over

time. Due to the higher moisture and collagen content of new bones, a perimortem break looks

different than a postmortem break.

The goals of this research were two-fold. The first was to determine if a methodology

could be developed to distinguish a postmortem bone fracture from a perimortem bone fracture.

The second goal was to establish a more reliable methodology for observing these fracture

pattern differences that could be applicable to both the fields of forensic science and

archaeology.

Due to the inaccessibility of a sufficient sample of human femora, deer bones were used

for this experiment. The experiment was carried out in a laboratory setting to control for as many

variables as possible. I compared two groups of bones: one group that was broken a few days

after death and another group that was broken approximately two months after death. I then

analyzed the bones for certain fracture patterns.

54

Previous research has explored fracture patterns in human bones, as well as other

mammal long bones in a variety of settings and states of decomposition (Degusta, 1999;

Johnson, 1985; Villa and Mahieu, 1991; Wheatley, 2008; Wieberg and Wescott, 2008). This

study included some variables used by previous researchers. As hypothesized, major findings of

the present study were that (a) perimortem fracture patterns in deer femora contained more acute

angles along the fracture surface, whereas postmortem bones were more likely to contain right

angles and (b) perimortem fractures were also more likely to have smooth surfaces at the break

site, as opposed to the postmortem group, which contained more rough surfaces.

A summary of results follow. Significant correlations were observed between bone

condition (old, new) and right angles (rho = -.463, p < .001, old bones tend to exhibit a right

angle); acute angles (rho = .415, p < .001, new bones tend to exhibit an acute angle); smooth

surface (rho = .379, p < .001, new bones tend to exhibit a smooth surface); and rough surface

(rho = -.420, p < .001, old bones tend to exhibit a rough surface).

Significant differences in curved edges were observed between proximal and distal ends,

regardless of bone condition (old, new). Curved edges were almost always found on the proximal

side of the surface fracture. Highly significant differences in smooth surfaces were observed

between proximal perimortem and proximal postmortem bones and between proximal

perimortem and distal perimortem bones. Highly significant differences in rough surfaces were

observed between proximal perimortem and proximal postmortem bones and between proximal

perimortem and distal perimortem bones. A significant difference in transverse fractures was

observed between proximal postmortem and distal postmortem bones. Finally, a significant

difference in radiating fractures was observed between proximal and distal bone ends regardless

of bone condition (old, new).

55

Results may be applicable to scientists in the fields of bioarchaeology and forensic

science; however, study results must be applied with caution to human cases. Although deer

bones are anatomically similar to human bones, the osteological differences between deer and

human bones may affect interpretation. It was found that certain variables were significantly

correlated with bone age (old, new) and bone end (proximal, distal), therefore supporting the

idea that there is a methodology to distinguish a postmortem bone fracture from a perimortem

bone fracture. Further research is necessary to determine which variables could be used to

accurately classify a fractured bone into perimortem or postmortem categories.

While the correlational statistic used in this study (Spearman's rho) is helpful to

understanding the relationship among variables, logistic regression analyses might allow for the

development of a model that could help to predict whether a bone is classified as perimortem or

postmortem based on the fracture pattern. Further research will be necessary to identify other

variables important to the development of a regression model. Findings of the present study are

applicable to both the fields of forensic science and archaeology. Statistical modeling may be

found to be useful in bridging the science of the present study with application in the field.

56

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trampling: an experimental application on the Level XII faunal record of Bolomor Cave (Valencia, Spain). Journal of Archaeological Science, 35(6), 1605-1618.

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of Physical Anthropology, 110(2), 215-241. Degusta, D. (2000). Fijian cannibalism and mortuary ritual: Bioarchaeological evidence from

Vunda. International Journal of Osteoarchaeology, 10(1), 76-92. Edgar, H. J. H., & Sciulli, P. W. (2006). Comparative human and deer (Odocoileus virginianus)

taphonomy at the Richards Site, Ohio. International Journal of Osteoarchaeology, 16(2), 124-137.

Fenton, T. W., Birkby, W. H., & Cornelison, J. (2003). A fast and safe non-bleaching method for

forensic skeletal preparation. Journal of Forensic Sciences, 48(2), 274-276. Henshilwood, C. S., d'Errico, F., Marean, C. W., Milo, R. G., & Yates, R. (2001). An early bone

tool industry from the Middle Stone Age at Blombos Cave, South Africa: implications for the origins of modern human behaviour, symbolism and language. Journal of Human Evolution, 41(6), 631-678.

Hurlbut, S. A. (2000). The taphonomy of cannibalism: A review of anthropogenic bone modification in the American Southwest. International Journal of Osteoarchaeology, 10(1), 4-26.

Janjua, M. A., & Rogers, T. L. (2008). Bone weathering patterns of metatarsal v. femur and the

postmortem interval in Southern Ontario. Forensic Science International, 178(1), 16-23.

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Johnson, Eileen (1985). Current Developments in Bone Technology. Advances in archaeological method and theory, 8, 157-235.

Lunney, G.H. (2005). Using analysis of variance with a dichotomous dependent variable: An

empirical study. Journal of Educational Measurement, 7(4), 263-269. Neri, R., & Lancellotti, L. (2004). Fractures of the lower limbs and their secondary skeletal

adaptations: A 20th century example of pre-modern healing. International Journal of Osteoarchaeology, 14(1), 60-66.

Niven, L. (2007). From carcass to cave: Large mammal exploitation during the Aurignacian at

Vogelherd, Germany. [Review]. Journal of Human Evolution, 53(4), 362-382. Steadman, D. W., Anton, S. C., & Kirch, P. V. (2000). Ana Manuku: A prehistoric ritualistic site

on Mangaia, Cook Islands (Cannibalism). Antiquity, 74(286), 873-883. Symes, S. A., Kroman, A. M., Rainwater, C. W., & Piper, A. L. (2005). Bone biomechanical

considerations in perimortem vs. postmortem thermal bone fractures: Fracture analyses on victims of suspicious fire scenes. American Journal of Physical Anthropology, 202-203.

Villa, P., & Mahieu, E. (1991). Breakage patterns of human long bones. Journal of Human

Evolution, 21(1), 27-48. Walker, P. L. (2001). A bioarchaeological perspective on the history of violence. Annual Review

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fracture patterns in deer femora. Journal of Forensic Sciences, 53(1), 69-72. White, Tim D. (1992) Prehistoric Cannibalism at Mancos 5MTUMR-2346. Princeton University

Press, New Jersey. Whyte, T. R. (2001). Distinguishing remains of human cremations from burned animal bones.

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Correlation between the postmortem interval, bone moisture content, and blunt force trauma fracture characteristics. Journal of Forensic Sciences, 53(5), 1028-1034.

58

58

APPENDIX A:

DEER FEMORA DATA COLLECTION SHEET

1. Case #________ 2. Condition: ___Wet (Fresh) ___Dry (Old) 3. Time since death: _______<4 days ________ > 60 days 4. Prox. Fract. Angle on Z Axis: ___Right Angles 5. Dist. Fract. Angle on Z Axis: ___ Right Angles 6. Prox. Fract. Angle on Z Axis: ___ Acute Angles 7. Dist. Fract. Angle on Z Axis: ___ Acute Angles 8. Prox. Fract. Surface Morphology: ____Smooth 9. Dist. Fract. Surface Morphology: ____Smooth 10. Prox. Fract. Surface Morphology: ____Rough 11. Dist. Fract. Surface Morphology: ____Rough 12. Prox. Fract. Outline: ___Transverse 13. Dist. Fract. Outline: ___ Transverse 14. Prox. Fract. Outline: ___Curved 15. Dist. Fract. Outline: ___ Curved 16. Prox. Fract. Outline: ___ Jagged 17. Dist. Fract. Outline: ___ Jagged 18. Prox. Edges: ______Sharp Peaks 19. Dist. Edges: ______Sharp Peaks 20. Prox. Edges: ______Spiral Fractures 21. Dist. Edges: ______Spiral Fractures 22. Prox. Fract. Lines: (How Many?)______ 23. Dist. Fract. Lines: (How Many?)______ 24. Butterfly fracture: ______ 25. # of pieces: ______ >10mm. not including epiphyses.

Amendment table

Datum# Notes

59

59

APPENDIX B:

CODEBOOK FOR FRACTURE PATTERN VARIABLES

VARIABLE DESCRIPTION VARIABLE NAME VALUES FORMATCase identification number CASEID 1 TO 174 F3.1 End of bone BONEEND 1. Proximal F1.0

2. Distal

Condition (or age) of bone when broken BONECOND 1. Old Proximal F1.0 2. New Proximal

3. New Distal 4. Old Distal

Does the bone have a right angles that encompass RIGHTANG 0. Absent F1.0at least 25% of the fracture surface? 1. Present Does the bone have a acute angles that encompass ACUTEANG 0. Absent F1.0at least 25% of the fracture surface? 1. Present Does the bone have jagged edges that encompass JAGGEDED 0. Absent F1.0at least 25% of the fracture surface? 1. Present

Does the bone have a curved edges that encompass at least 25% of the fracture surface?

CURVED 0. Absent F1.01. Present

Does the bone have smooth edges that encompass SMOOTHFR 0. Absent F1.0at least 25% of the fracture surface? 1. Present

Is the bone surface along the Z-axis fracture line rough for at least 25% of the circumference?

ROUGHFRA 0. Absent F1.01. Present

Does the bone have a transverse fracture along the Z-axis encompassing at least 75% of the circumference?

TRANSVER 0. Absent F1.0

1. Present Does the bone contain any butterfly fractures? BUTTERFL 0. Absent F1.0 1. Present How many fracture lines does the bone have? RADIATIN Continuous F2.0 Into how many pieces did the bone break? NUMBEROF Continuous F2.0 Descriptive data. Note anomalies here. NOTES

60

60

APPENDIX C:

CORRELATIONAL TABLE

* Correlation is significant at the .05 level (2-tailed) **Correlation is significant at the .01 level (2-tailed)

Variable Correlation/Significance BONE

CONDITIONRIGHT

ANGLES ACUTE

ANGLES BONECONDITION Correlation Coefficient 1.000 -.002 -.073

Sig. (2-tailed) . .981 .342 RIGHTANGLES Correlation Coefficient -.002 1.000 -.614**

Sig. (2-tailed) .981 . .000 ACUTEANGLES Correlation Coefficient -.073 -.614** 1.000

Sig. (2-tailed) .342 .000 . JAGGEDEDGES Correlation Coefficient .156* -.190* .119

Sig. (2-tailed) .040 .012 .117 CURVEDEDGES Correlation Coefficient -.272** -.129 .147

Sig. (2-tailed) .000 .089 .053 SMOOTHFRACTURESURFACE Correlation Coefficient -.290** -.203** .219**

Sig. (2-tailed) .000 .007 .004 ROUGHFRACTURESURFACE Correlation Coefficient .165* .250** -.206**

Sig. (2-tailed) .030 .001 .006 TRANSVERSEFRACTURE Correlation Coefficient .267** .259** -.247**

Sig. (2-tailed) .000 .001 .001 BUTTERFLYFRACTURES Correlation Coefficient -.065 .196 -.255*

Sig. (2-tailed) .549 .069 .017 RADIATINGFRACTURELINES Correlation Coefficient .435** -.046 .006

Sig. (2-tailed) .000 .543 .932 NUMBEROFPIECES Correlation Coefficient .062 -.210 .260*

Sig. (2-tailed) .570 .051 .015 OLDVSNEW Correlation Coefficient .000 -.463** .415**

Sig. (2-tailed) 1.000 .000 .000

61

Correlational table, continued


Variable Correlation/Significance JAGGED EDGES

CURVED EDGES

SMOOTH FRACTURESURFACE

BONECONDITION Correlation Coefficient .156* -.272** -.290**

Sig. (2-tailed) .040 .000 .000 RIGHTANGLES Correlation Coefficient -.190* -.129 -.203**

Sig. (2-tailed) .012 .089 .007 ACUTEANGLES Correlation Coefficient .119 .147 .219**

Sig. (2-tailed) .117 .053 .004 JAGGEDEDGES Correlation Coefficient 1.000 -.163* -.294**

Sig. (2-tailed) . .031 .000 CURVEDEDGES Correlation Coefficient -.163* 1.000 .326**

Sig. (2-tailed) .031 . .000 SMOOTHFRACTURESURFACE Correlation Coefficient -.294** .326** 1.000

Sig. (2-tailed) .000 .000 . ROUGHFRACTURESURFACE Correlation Coefficient .298** -.251** -.770**

Sig. (2-tailed) .000 .001 .000 TRANSVERSEFRACTURE Correlation Coefficient .112 -.825** -.278**

Sig. (2-tailed) .143 .000 .000 BUTTERFLYFRACTURES Correlation Coefficient -.009 -.045 -.078

Sig. (2-tailed) .937 .678 .472 RADIATINGFRACTURELINES Correlation Coefficient .296** -.222** -.313**

Sig. (2-tailed) .000 .003 .000 NUMBEROFPIECES Correlation Coefficient .121 .173 .128

Sig. (2-tailed) .263 .110 .238 OLDVSNEW Correlation Coefficient -.027 .037 .379**

Sig. (2-tailed) .726 .624 .000

62



Variable Correlation/Significance

ROUGH FRACTURESURFACE

TRANS-VERSE

FRACTURE

BUTTER-FLY

FRACTURESBONECONDITION Correlation Coefficient .165* .267** -.065

Sig. (2-tailed) .030 .000 .549 RIGHTANGLES Correlation Coefficient .250** .259** .196

Sig. (2-tailed) .001 .001 .069 ACUTEANGLES Correlation Coefficient -.206** -.247** -.255*

Sig. (2-tailed) .006 .001 .017 JAGGEDEDGES Correlation Coefficient .298** .112 -.009

Sig. (2-tailed) .000 .143 .937 CURVEDEDGES Correlation Coefficient -.251** -.825** -.045

Sig. (2-tailed) .001 .000 .678 SMOOTHFRACTURESURFACE Correlation Coefficient -.770** -.278** -.078

Sig. (2-tailed) .000 .000 .472 ROUGHFRACTURESURFACE Correlation Coefficient 1.000 .203** -.019

Sig. (2-tailed) . .007 .858 TRANSVERSEFRACTURE Correlation Coefficient .203** 1.000 .045

Sig. (2-tailed) .007 . .678 BUTTERFLYFRACTURES Correlation Coefficient -.019 .045 1.000

Sig. (2-tailed) .858 .678 . RADIATINGFRACTURELINES Correlation Coefficient .256** .225** -.019

Sig. (2-tailed) .001 .003 .860 NUMBEROFPIECES Correlation Coefficient -.067 -.173 -.230*

Sig. (2-tailed) .538 .110 .032 OLDVSNEW Correlation Coefficient -.420** -.008 -.065

Sig. (2-tailed) .000 .915 .549

63



Variable Correlation/Significance

RADIATINGFRACTURE

LINES NUMBER

OF PIECES OLD VS

NEW BONECONDITION Correlation Coefficient .435** .062 .000

Sig. (2-tailed) .000 .570 1.000 RIGHTANGLES Correlation Coefficient -.046 -.210 -.463**

Sig. (2-tailed) .543 .051 .000 ACUTEANGLES Correlation Coefficient .006 .260* .415**

Sig. (2-tailed) .932 .015 .000 JAGGEDEDGES Correlation Coefficient .296** .121 -.027

Sig. (2-tailed) .000 .263 .726 CURVEDEDGES Correlation Coefficient -.222** .173 .037

Sig. (2-tailed) .003 .110 .624 SMOOTHFRACTURESURFACE Correlation Coefficient -.313** .128 .379**

Sig. (2-tailed) .000 .238 .000 ROUGHFRACTURESURFACE Correlation Coefficient .256** -.067 -.420**

Sig. (2-tailed) .001 .538 .000 TRANSVERSEFRACTURE Correlation Coefficient .225** -.173 -.008

Sig. (2-tailed) .003 .110 .915 BUTTERFLYFRACTURES Correlation Coefficient -.019 -.230* -.065

Sig. (2-tailed) .860 .032 .549 RADIATINGFRACTURELINES Correlation Coefficient 1.000 .279** .089

Sig. (2-tailed) . .009 .245 NUMBEROFPIECES Correlation Coefficient .279** 1.000 .062

Sig. (2-tailed) .009 . .570 OLDVSNEW Correlation Coefficient .089 .062 1.000

Sig. (2-tailed) .245 .570 .

64

APPENDIX D: DESCRIPTION OF DEPENDENT VARIABLES

Variable Classification Statistic Right Angles: Right angled fractures are thought to be found more frequently in postmortem breaks

Ordinal: Absent (0) or Present (1) Dichotomous: 0/1

Spearman correlation MANOVA

Acute Angles: Acute angled fractures are thought to be found more frequently in perimortem breaks



Jagged Edges: Jagged edges along the Z-axis are thought to be found more frequently in perimortem breaks



Curved Edges: Curved edges are thought to be found more frequently in perimortem breaks



Smooth Surfaces: Smooth bone surface along the Z-axis fracture line are thought to be found more frequently in perimortem breaks



Rough Surfaces: Rough bone surface along the Z-axis fracture line are thought to be found more frequently in postmortem breaks



Transverse Fractures: Transverse fractures are thought to be found more frequently in postmortem breaks


Spearman correlation ANOVA

Butterfly Fracture: Butterfly fractures are thought to be found more frequently in perimortem breaks


Spearman correlation

Fracture Lines: Number of fracture lineare thought to be found more frequentlyin postmortem breaks

Continuous Spearman correlation ANOVA

Number of Pieces: Number of pieces created during the breaking of the bone are thought to be found more frequently in perimortem breaks

Continuous Spearman correlation

perimortem and postmortem fracture patterns by...

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