intro – physical trauma

Intro – Physical Trauma

• Physical trauma: any mild, serious, or life-threatening body damage caused by physical impact– Types we will be studying:

• Abrasions• Contusions • Lacerations • Chop wounds• Incised wounds• Therapeutic wounds• Hesitation marks

Case Study: The Siren and the Slugger

Agree or Disagree?

• Based on what you currently know about the case, do you think Chris Brown was in the right?

• Everyone out of your seats. Stand near the doorway if you AGREE with the above statement. If you DISAGREE, stand by the back window. If you are unsure, stand by the front table.

Case Study: Chris Brown and Rihanna• The Situation:

– Just after midnight on Sunday, February 9, 2009, police were called to the scene of a dispute in Los Angeles, CA. At the scene, officers encountered a rented Lamborghini sports car and a young woman who had visible injuries from a physical assault. The young woman was later identified as Grammy Award-winner Rihanna.

• Background:– Rihanna had been romantically involved with fellow

recording artist Chris Brown for more than a year.– That night, the pair was traveling in the rented

sports car through the Hancock Park area of Los Angeles.

– At that time, a verbal disagreement began about a text message Brown had received from a woman with whom he had had a previous relationship.

– Brown tried to halt the argument by pulling the vehicle over and attempting to force the female singer from the car.

• Background, Cont’d– When Rihanna refused to exit the vehicle, Brown

shoved Rihanna against the window with sufficient force to cause a raised circular contusion to form on her forehead.

– Then, he began to punch her in the face. Rihanna attempted to protect herself by covering her face and head with her arms.

– The force and number of blows resulted in numerous contusions on her left hand and a large contusion to her left triceps.

• Background, Cont’d– Brown then placed Rihanna in a headlock and bit her

left ear. Brown stopped the car and began to choke Rihanna until she attempted to gouge his eyes. He bit her left ring and middle fingers and then released her. She turned to face him, placed her feet on his chest, and pushed him away.

– He continued to punch her legs and feet, causing several more contusions.

– When Rihanna began screaming for help, Brown got out of the vehicle and walked away from the scene.

– A resident in the neighborhood heard Rihanna's cries and called 911.

• The Proceedings:– When the police arrived, they processed the

scene, took a statement from Rihanna, and sent the singer to the hospital for treatment. At the hospital, photographs were taken of her injuries for documentation of domestic abuse.

– At about 7:00pm that evening, Brown turned himself in at a Los Angeles police station. In June 2009, Brown pled guilty to a charge of felony assault and received a sentence of five years’ probation, six months of community service, and one year of domestic violence counseling.

Agree or Disagree?

• With the evidence provided by the police report, do you think Chris Brown was in the right?

• Everyone out of your seats. Stand near the doorway if you AGREE with the above statement. If you DISAGREE, stand by the back window. If you are unsure, stand by the front table.

Exit Slip - Survey

• Write a Yes or No in your portfolio next to your entry from earlier to answer the following question:

In the next several classes, we will be looking at and discussing pictures of different types of physical trauma. Would you feel at all uncomfortable doing this?

Crime in the United States

Impressions Activity!

• What is an impression in forensic science?

Making an Impression – Part 1

• We will analyze our own impressions using measurements and observations– On a piece of paper, create a data table that will

show:• 1. the width (cm) of your maxilla and mandible• 2. the depth (cm) of your maxilla and mandible• 3. observations of the unique characteristics of your

teeth marks (slanted teeth, spaces, evidence of braces, etc.)


• Materials – 1 per student:– Styrofoam plate– Permanent marker (need to share)– Ruler – Overhead transparency

Making an Impression – Part 1• Bend plate in half – top of plate will be inside• Label the top half “Maxilla” and the bottom “Mandible”• Push the plate as far back as it will go in your mouth

and bite down – not too hard – you don’t want to break through the plate!

• Place your transparency over your plate and trace your dental pattern as accurately as possible.

• Don’t forget to label your transparency – maxilla and mandible

• Make your measurements and record data in your table


• On the same piece of paper from Part 1, create another data table that will show:– 1. data for 4 different materials you will be testing– 2. data includes a rating for each material and– 3. observations for each material – did the material

give a good impression? Why or why not?

Making an Impression – Part 2• I will need 3 people to help pass out ONE of each of the

following:1. Circus Peanut2. Swedish Fish3. Laffy Taffy4. Star Burst– You will place the candies on your plate and make an

impression + write observations and ratings for each candy. Don’t eat the candy until you have written your observations in your data table. You can eat everything except the circus peanut

– NOTE: Please complete the circus peanut first – I will come around and collect these as you work. You will need to label the maxilla side (MX) and the mandible side (MN)

Making an Impression - Challenge• At the front of the room I have your collected

circus peanuts and transparencies. You may work in groups with as many people as you like.

• One person from each group come and collect enough peanuts and transparencies for each person in your group.

• Try to make matches – if you think you have one, call me over and I’ll come check. The first 5 people to have a match can have another piece of candy of your choice.

Making an Impression – Wrap-Up

• On the paper with your data tables, write a short paragraph to summarize what you have learned about identifying bite marks. Be sure to include:– The process– How different materials affected the

appearance/observations

Bite Marks• Types of crime involving

bite marks:– Abuse– Assault– Sexual assault– Homicide– Exceptional cases such as

bank robberies

• It is important to remember that bite marks can be both attack injuries (and therefore present on the victim) and defensive wounds (and therefore present on the suspect) and all individuals suspected of involvement in a crime against a person need to be examined for such marks.

Bite Marks• It is important that

dentists, doctors, police officers, social workers, and forensic pathologists know the most common locations to be able to analyze a situation

• Doctors and dentists, when presented with bite mark wounds, must document what they see and keep records of this info.

Bite Marks - Anatomical Location• In a study, 148 bite marks

were analyzed to determine most common victims and anatomical locations

• Females were 4X more likely to be bitten, and over 50% of males were suspects in the case

• Females more likely to be bitten on breasts, arms, and legs; children on genitals, legs, and back; males on hands, back, or face

Presentation of bite mark injuries• Typically present as elliptical or circular injuries, with

separation near the halfway point• There is usually an absence of bruising or a diffused bruise in

the center• Sometimes, only one arch of teeth is seen – most often the

lower jaw– Why?

Warm-Up

• Using what you know about the integumentary and circulatory systems, describe how bite marks or other types of contusions form. – In your description, use at least three of the

following words: epidermis, dermis, hypodermis, blood, veins, arteries, capillaries

3 main factors that influence the severity of injury:

• The force by which the injury was inflicted• The anatomical location of injury (Why?)• The time elapsed between the time bitten and

presentation to the doctor/ odontologist

Collection of bite mark evidence

• So far we’ve discussed two aspects of forensic significance of identifying bite marks. What were they?

• The third – the QUALITY OF EVIDENCE COLLECTION!– How do you think they collect evidence?– Who is “they?”– What might affect the quality?


• Evidence is collected from both the victim and suspect– Review: how? What do investigators look at?


• Evidence is collected from both the victim and suspect– Review: how? What do investigators look at?– Pictures of victim’s whole body (without scale),

zoomed in picture of wound with scale (see below)– Measuring length and width of both maxilla and

mandible– Finding unique characteristicssuch as gaps between teeth, misaligned teeth, etc.

Physical Trauma – in general• Forensic nurses evaluate physical trauma

and interpret injuries to look for clues regarding the events that lead up to the crime

• Some injuries can provide a profile of the suspect (what does this mean?)

• The location of the trauma on victim’s body helps determine how tall perpetrator is and position of victim at time of attack

• Angle of impact helps determine if perpetrator is left- or right-handed

Evidence of physical trauma

• Appearance and extent of injuries depends on the following:– The amount of force applied to the body– The weapon’s surface area and mass– Anatomical location

Force

• Review: What is force?

Force• Force = mass x acceleration(acceleration is the change in speed over time; speeding up or slowing down)• The important thing to remember here is the

relationship between mass, force, and acceleration.– So an object with larger mass that is moving

quickly upon impact will cause a more serious injury

– Smaller objects or slowly moving objects upon impact will cause less serious injuries

Example

• High speed accident: • Low speed accident:

Today we will be learning about:

• How investigators classify injuries to the body:– Blunt force trauma

• Caused by victim hit by something hard• Caused by falls or is pushed into a hard object

– Sharp force trauma• Stab wounds• Incised wounds• Chop wounds• Therapeutic wounds

Blunt Force Trauma - Abrasions• When the skin rubs against a rough

surface, an abrasion forms– Examples?

– Abrasions are deep/not deep?

– In life, they appear reddish-brown and heal relatively quickly

– Postmortem (?), abrasions appear yellow, almost transparent

3 Types of abrasions• Brush: when force is

applied parallel to skin; epidermis is scraped off in layers; skin damaged in direction of force

• Impact: when force applied perpendicular to skin, skin is crushed; most commonly seen on bony parts of body

• Patterned: if object that caused impact or brush abrasion leaves an impression; these leave unique clues about weapon used

Blunt Force Trauma - Contusions • Bruises caused by broken blood vessels deep in the skin• Usually not fatal, but if a victim sustains many at once,

he/she may suffer severe blood loss, which could lead to shock and death (what is shock?)

• Can also form on internal organs such as ?– When internal contusions form, the collected blood can cause

swelling – this is called ?– How can doctors/investigators see internal contusions?– Severity of contusions is based on – think back to bite marks!

• 1. • 2. • 3. general health of the victim – who do you think might bruise more

easily?

Blunt Force Trauma - Lacerations• Tear in the tissue (which tissues?) caused by an

extreme sliding or crushing force– Blunt objects, falls, vehicle accidents– Marks produced have irregular edges, but sometimes

patterned – since skin tears it does not usually hold the unique shape of the pattern

– May occur internally or externally

Sharp Force Trauma – Stab Wounds • Sharp force trauma caused by incised wounds

that are shorter in length than they are deep in the body

• Most are caused by single-edge kitchen, pocket, or folding knives

• Wounds that result in a punctured organ are called penetrating wounds

• Wounds that puncture an organ and come out the other side of the organ are called perforating wounds

Sharp Force Trauma – Incised Wounds• Also called cuts; are produced by any object

with a sharp edge such as a knife, glass, metal, or even paper

• Difference from stab wound – the wounds are longer than they are deep

• Usually the force is applied parallel to the body, so these types of wounds do not give good clues about the weapon used

Sharp Force Trauma – Chop Wounds• Produced by heavy tools such as axes,

machetes, swords, meat cleavers, etc.• Produce incised wounds on the surface of

the body as well as deep internal injuries, including bone fractures

• What clues might investigators use to identify this type of wound and the weapon used?

Sharp Force Trauma - Therapeutic

• Any incision made in a medical setting– Surgery– Biopsy – Others?

Check In – can you identify the types of wounds?

• Is this a sharp force or blunt force wound?• Which type of sharp or blunt force is it?

Laceration Incised Wound

Cause Blunt force trauma Sharp force trauma

Edges Ragged/ irregular Cleanly divided

Bruising/abrasions? Yes No

Depth Variable Can be uniform

Presence of tissue bridging? Yes No

Position Particularly bony prominences Any location

Presence of foreign bodies? Often contaminated wounds Usually clean (unless caused by glass)

Hairs Intact hairs may cross the wound Hairs are cleanly divided

Bony injury May have associated fractures Scoring or chipping of bone may occur

Healing 2° intention (with extensive scarring)

1° intention – good if wound edges apposed. Generally leaves fine scarring

Read more: http://www.forensicmed.co.uk/wounds/sharp-force-trauma/

http://www.forensicmed.co.uk/wounds/sharp-force-trauma/?utm_source=copy&utm_medium=paste&utm_campaign=copypaste&utm_content=http://www.forensicmed.co.uk/wounds/sharp-force-trauma/

Intro to Autopsy - Lividity

• When a person dies, the heart stops pumping blood through the body– Where do you think the blood goes?

Intro to Autopsy - Lividity

• Blood pools downward with the force of gravity– What do you think this looks like?

– Lividity begins to appear ~30 minutes – 2 hours after death and continues to become more apparent (darker) for up to 12 hours

• Why does it become darker?– What happens after the body is cooled down?

We will talk about Autopsy next• We will learn about how medical

examiners identify time of death, manner of death, mechanism of death, and cause of death, as well as how they document their findings

Death Investigation and Autopsy

• What is an autopsy?

• What is the purpose of an autopsy?

Autopsy in a nutshell• What is the purpose of an autopsy?

– Medical examination, postmortem– Performed if the cause of death is not known, to

document injuries, to exclude other causes of death, and to determine factors that contributed to death

– The report typically includes a heading, information about the internal and external examinations, description of any evidence of injury, and the medical examiner’s findings and opinions

Report:

By law, a death must be investigated if:• It was a violent crime, suicide, or accident• It occurred within 24 hours of entering a

hospital or as result of surgery• It was a natural death and the patient was not

under care of a doctor• It occurred in police custody or in a

correctional facility• The death resulted from a communicable

disease that may pose a threat to public health

Medical examiner determines:• Time of death – how?• Manner of death – what is this?

• Manner of death is the way a person dies:Manner of Death Description

Natural Most common; body function failure as a result of age, illness, or disease

Accident UnintentionalSuicide Victim intentionally takes his or her

own life; cause of death is usually a gunshot, hanging, or poisoning

Homicide One individual takes the life of another intentionally or through a negligent or reckless act; court decides if it is murder; sometimes the result of self-defense

Undetermined The pathologist is unable to determine the manner of death, even after all internal and external exams and toxicological tests are evaluated

Death Investigation – 3 steps1. At the death scene – preliminary

investigation2. Medical examination (autopsy) – external

and internal investigations3. Lab tests on biological evidence collected

during autopsy

At the Death Scene• CSIs take photos and make sketches of the body at the

scene to – Document position of the body – ID the face later on– Underneath body to record lividity, blood, and possible trace

evidence• Document any signs of trauma• Document signs of

– Livor mortis – dark coloring from pooling of blood (appears 30 mins – 2 hrs after death; becomes fixed 8-12 hrs after death)

– Rigor mortis – stiffening of body due to lack of ATP in muscle cells (appears 2 – 4 hrs after death; subsides within 36 hrs)

– What does this help determine?

At the Death Scene• CSIs look for scene markers – what might these

be?• Investigators protect victim’s hands and feet

before transporting – why?• While body is being processed and transferred,

investigators begin to interview witnesses • Once identified, investigators interview family,

review victim’s medical history and police reports

Medical Examination - External• Purpose of autopsy – to determine manner,

mechanism, and cause of death • At the morgue, medical examiner looks at

external body, documents trauma• Looks at clothes – what might this tell about

what happened?• Biological, nonbiological, and trace evidence

are collected, preserved, and processed in lab– Examples of each?

• X-rays are ordered

Medical examination - Autopsy• What is algor mortis?• How do they take internal temp?

• Time since death = Normal body temp (F) – current body temp

1.4

Medical Examination - Autopsy• After estimating time of death, medical

examiner removes:– Brain– Larynx– Hyoid bone– Heart– LungsWhat might these organs tell the examiner?

Medical Examination - Autopsy• Fluids collected – blood, urine, bile

– For what?• Internal organs then removed – mass is

recorded• Stomach contents are analyzed

– What kinds of clues can be found here?

Laboratory Analysis• Toxicology• Histology• Neuropathology• Serology

intro – physical trauma

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