Differentiating Blunt Force Trauma:

Vehicular Trauma Versus Vertical

Fall

Selene Cannelli

ANTH 4420

Faculty Adviser: Dr. Susan Kirkpatrick Smith

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Abstract

This project has the purpose to understand if it is possible

to know what caused specific bone fractures. The project focused

on bone fractures caused by a car hit and by a fall from a

cliff. Two subjects were considered: a dog hit by a car, and a

baby pig thrown by a cliff postmortem. I will examine the bones in

order to document the type of fracture caused by the two different

types of impact, and if they have a specific pattern. I expect

this research to show different kind of trauma from those hits.

This project will be helpful in murder cases. Researches can

understand if a body found on the bottom of a cliff felt from that

cliff, or if it was moved there and the real crime scene is

somewhere else.

IntroductionStudies to distinguish different types of traumas have been

conducting, but most research is based on projectile and sharp

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traumas (Michael et al. 2003; Thali et al. 2003; Alunni-Perret et al. 2005;

Moraitis et al. 2009). The studies conducted about blunt force trauma

have been all concentrating in comparing them with sharp trauma or

projectile trauma (Ambade and Godbole 2006; Kremer and Sauvageau

2009

This project has the purpose to understand if it is possible

to know what caused specific blunt bone fractures. The research

focused on bone fractures caused by being hit by a car and by

falling from a cliff. Two subjects were considered: a dog hit by a

car and a juvenile pig thrown from a cliff. Other similar cases on

academic journals were considered for comparisons, and to

understand how the different kind of bone fractures look like.

This research can be used in police cases to understand if a

body, found on the bottom of a cliff, died from the fall or it was

moved there postmortem and the actual place where he died was on

the road because hit by a car. More researches need to be done to

be sure of these results, and to see different patterns of

fractures, and maybe as well recurring patterns.

Materials and Methods

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The pig weighed 30.15 pounds. It was dropped from a cliff of

38 feet height postmortem. Before hitting the bottom it bounced

along the rocks. The dog was found on the side of a road after

being hit by a car. It was buried and excavated after

approximately 5 years. Both skeletons are incomplete. Figure 1 is

showing the percentage of how much complete are the two skeletons.

The dog is missing most of the skull, which is fragmented and just

the right mandible is complete, both of the patellae, four ribs,

four thoracic vertebrae, one lumbar vertebra, two caudal

vertebrae, the sternum and six phalanges. The pig skeleton is more

complete than the dog, but it is missing the sacral bone, two

cervical vertebrae, five caudal vertebrae, the sternum.

Injuries were documented based on non-metric analysis to

locate and identify the different bone fractures (Byers 2011;

Lovell 1997). There was no evidences of sharp and projectile

trauma fractures on the bones (Alunni-Perret et al 2005; Thali et al.

2003; Lovell 1997).

I tried to understand as well which type of forces caused the

fractures on the bones. The force was documented if the bone had

the following features:

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, between tension, compression, torsion, bending and shearing

force, referring to Moraitis and Spiliopoulou (2006) article, and

Byers (2011).

I compared the pattern of trauma on each skeleton.

Results

Both the skeletons presented just blunt force trauma (figure

4). Three types of trauma where present on each skeleton: bending,

compression and shearing. Binding was on the skull, vertebrae,

sacrum, right and left os coxae, left fibula of the dog. On the

pig the following bones were fractured by binding force: skull,

five lower teeth and three upper teeth, transverse and spinous

process of some vertebrae, ribs, left scapula, left and right

radius, two carpal, left talus, right and left os coxae.

Compression force was found just in the pig vertebrae bodies and

three ribs, while shearing force caused fractures in the dog

scapula, first rib and right femur (Table 1).

Most of the fractures found on the pig bones were caused by

the bending force. Compression force was the cause of the injuries

on the vertebrae, which most of them have the body detached, and

what caused most of the epiphysis to detach from the rest of the

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bone. Also three ribs showed fractures caused by compression force

(Daegling et al 2008; Lovell 1997). The vertebrae and ribs are

bones that show more injuries. The long bones of anterior and

posterior legs were intact, except the right and left radius. The

skull and the paws bone did not show many fractures, just two

carpals broke and the left talus. The skull has five broken from

the mandible and three maxilla broken teeth. The only other damage

is on the occipital bone, where the occipital condyles broke apart

from the skull, but did not present any other type of injuries.

Bending force was also the cause of most fractures on the dog.

The fractures on the scapulae, the first rib, right femur and left

iliac crest were a consequence of shearing force (Byers 2011;

Lovell 1997). The bones that presented the most damages are the

skull, which just few fragments are left with the mandibles, the

pelvic girdle and the posterior legs.

The pig shows more fractures than the dog. Also the pig

fractures were more spread out through the skeleton, than

localized in specific areas as in the dog (figure 5). The number

of complete fractures is greater in the pig, however the dog shows

more incomplete fracture than the pig.

Discussion

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From the location of the fractures it could be that the pig

hit the ground on his back, which will explain the fractures that

the 22 vertebrae have, as the almost integrity of the skull, which

would have hit the ground after the vertebrae because just the

occipital condyles and some teeth broke apart. The other fractures

were most likely caused by bouncing on the rocks before touching

the ground. The dog was probably hit by a car first on his lower

back legs, which inhibit him to walk. Later it was hit a second

time on the skull.

The location, number of fractures, and the forces that caused them

will help to distinguish between a fall from a cliff and a hit by

a car.

• In case of fall: fractures will be spread all over the

skeleton, the higher the fall, the greater number of

fractures (Kremer and Sauvageau 2009).

• In case of car hit: fractures will be located in the area of

the hit. Other fractures could be present when the body

bounces the floor after the hit, but they would not show

serious injuries.

• A body that fell from a cliff will present more fractures

than a body hit by a car.

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• The type of force that induced the fractures will be of great

help to distinguish between the two trauma. Binding and

compression forces will be the cause of trauma in case of

fall. Binding and shearing forces will be the cause of trauma

in case of a hit (table 1).

• If a body was hit by a car, it will show less complete

fracture than a body fallen from a cliff, but more incomplete

fractures (figure 1) .

• If just bending forces are present it could still be possible

to understand which accident, from these two types, caused

the fractures. If a car hit was the cause, the skeleton will

show fracture lines and few complete fractures, those

fractures will also be localized in the area of impact. In

the case of a fall there will be more complete fractures than

fracture lines and the fractures will be all over the

skeleton.

To have accurate results more researches and experiments need to

be done. The experiments could be conducted with different weights

of an animal, because distinct weights could show different

injuries pattern, and with different objects hitting the body at

different speeds. In the case of a fall the same can be done, but

this time by throwing the body from different heights and with

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different rock formations. With those experiments I hope to see

distinct patterns for a fall and for a car hit, as well as

different patterns of fractures between a fall and a car hit.

During the analysis at the bone fractures I noticed that all

of them had a specific length. Thus I measured this length and

tried to see if a pattern of length occurred. I suppose that the

length is affected both from the force of the hit and, in the case

of a fall from the high the body is falling. I did not find any

researches about this theory, thus it can be that is completely

wrong, also because it is necessary to analyze more subjects to be

completely sure.

A blunt force trauma is an injury where the force has a wide area

of impact on bone (as a car). This trauma has the following

effects on bones: LeFort fractures, inbending at where the force

was applied, outbending around the site of force, ring fracture.

Blunt trauma are usually caused by bending or tension forces

(Byers 2011; Moraitis and Spiliopoulou 2006; Lovell 1997).

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Bending force usually impact the bone at a right angle, which will

cause a triangular break through its cross section. This force

could cause fracture lines at the point of impact or on the

opposite side of the break. If the force is strong enough, it can

cause a complete fracture. Compression force instead pushes inward

from the end of a bone. It could arouse complete fracture and/or

fracture lines, which can radiate from the point of impact.

Shearing force I happens when one segment of the bone is

immobilized and the other part of the bone is bent. This force

will show a linear shearing or diagonal type of fracture. Injuries

from this force usually occur in accidents, as a person trying to

stop him from falling, but it could be caused by a blow from a

large instrument or object as well (Byers 2001).

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Figure 4. Left broken os coxae of dog (left) and pig (right). Black arrows indicate complete fractures caused by binding force. Red arrow indicate green stick fracture

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Complete Skeleton

Complete Fractures

Bone with DemageBone with No Demage

No Complete FracturesDogPig

Figure 1. Comparing pig and dog skeletons

Dog Pig

Binding Skull, Vertebrae,Sacrum, Right and Left Os Coxae, Left Fibula.

Skull, Five lower Teeth and Three upper Teeth, Transverse and Spinous Process of some Vertebraeare missing, Ribs, Left Scapula, Left and Right Radius, Two Carpal, Left Talus, Right and Left Os Coxae

Compression

Vertebrae Bodies, Three Ribs,

Shearing Scapulae, First Rib, Right Femur.

Table 1. Comparison of trauma forces

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Figure 5. Fractures in dog and pig skeletons

Figure 6. Blunt force trauma caused by compression force. Rib of the juvenile pig.

Left Side

Right

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Figure 3.

Dog rib. Green stick fracture caused by

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Bibliography

Ambade, Vipul Namdeorao, and Godbole, Hemant Vasant 2006 Comparison of Wound Patterns in Homicide by Sharp andBlunt Force. Forensic Science International 156: 166–170.

Byers, Steven N. 2011 Introduction to Forensic Anthropology, 4th edition. NewJersey: Pearson.

Daegling, David J., Warren, Michael W., Hotzman, Jennifer L., andSelf, Casey J.2008 Structural Analysis of Human Rib Fracture and Implicationsfor Forensic Interpretation. Journal of ForensicSciences 53(6): 1301-1307.

Kremer, Clia, and Sauvageau, Anny 2009 Discrimination of Falls and Blows in Blunt Head Trauma:Assessment of Predictability

Through Combined Crtiteria. Journal Forensic Science54(4): 923-926.

Konstantinos Moraitis, and Chara Spiliopoulou 2006 Identification and differential diagnosis of perimortemblunt force trauma in tubular long Bones. Forensic Science, Medicine, and Pathology 2(4):221-229.

Lovell, Nancy C. 1997 Trauma Analysis in Paleopathology. Yearbook of PhysicalAnthropology 40:139–170.

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Luı´s Coelhoa, and Hugo F.V. Cardoso 2013 Timing of blunt force injuries in long bones: The effectsof the environment, PMI length and human surrogate model. Forensic Science International233: 230–237.

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