Forensic Pathology and Odontology

1. Forensic Pathology and Odontology

2. What is Forensic Pathology? • Definition: - investigation of sudden, unnatural, unexplained or violent deaths - notice: not all deaths warrant autopsy Ex. Old age, terminal illness - but violent, suspicious deaths in healthy individuals and some accidental deaths warrant the use of an autopsy (post-mortem examination of a body to determine cause of death)

3. Modern Goals of Autopsies • Determine the identity of the decedent • Determine the cause of death • Determine the manner of death • Determine the mechanism of death • Determine time of death

4. Cause and Manner of Death Cause of Death Manner of Death • the injury or disease that initiated death • Ex. cancer • explains how the cause arose; such as natural, accident, homicide, suicide (sometimes undetermined) • Ex. Struck by lightening (accident)

5. The Medical Examiner • Requires a Doctor of Medicine Degree • Responsibilities include autopsy, histology, and forensic photography • Perform around 250 autopsies a year • Review around 1,400 filed medical examiner cases a year • Provide instruction in Forensic Pathology • Salary: $97,000 - $170,000 a year* *Source: The Forensic Casebook pg. 174-175

6. Examination Protocol • Most ME’s visit the scene • Dental/medical history can be provided if identity of victim is known • Any use of resuscitation, injections, IV or thoracic lines, intubations, or bare-handed handling by medical personnel is vital knowledge

7. Examination Protocol • Visual inspection • Injury inspection • Internal examination • Presentation to other experts • Reconciliation of all exhibits • Presentation of findings

8. Three Types of Decomposition Rigor mortis: • medical condition that occurs after death and results in the shortening of muscle tissue and the stiffening of body parts in the position they are when death occurs • Immediately following death, muscles relax and then become rigid • Occurs in the first 24 hours and disappears within 36 hours

9. Three Types of Decomposition Livor mortis: • Medical condition that occurs after death and results in the settling of blood in areas of the body closest to the ground • Skin appears as a dark blue or purple in the areas where the blood has settled due to gravity • Begins immediately following death and lasts up to 12 hours after death

10. Three Types of Decomposition Algor mortis: • Postmortem changes that cause a body to lose heat until it reaches room temperature • Good for determining time of death • Average heat loss: 1 degree F per hour • Affected by clothing, weather conditions, fat content

11. Visual Inspection • Before the visual inspection begins, blood is drawn, X-rays taken, and inspected for sharps • Visual examination can begin with a nude or clothed body • Entire body is photographed

12. Visual Inspection cont… • Clothing is examined for rips, tears, or trace evidence • Clothing is removed, dried, & packaged; descriptions of clothing (including size/brand) recorded for autopsy report • Blood-stained clothing sent out for examination; blood stains on body swabbed for identification • Head combed for trace, foreign hairs, & other evidence

13. Visual Inspection cont… • Rape kit may be included at this stage if warranted • Body openings (ears, vagina, etc.) examined for foreign objects/trace evidence • Hands (bagged at the scene) are examined; fingernail scrapings • Fingerprint/footprint cards taken • Entomological samples taken if needed • Notations of visual injuries are made & photographed; tattoos/body markings noted • General health noted along with hair & eye color

14. Visual Inspection cont… • UV photography used to reveal old bruises or new ones not yet surfaced • Lasers/oblique lighting turn up trace such as hair, pollen, blood, saliva, semen, even fingerprints • Birthmarks, tattoos, & distinguishing scars used as recognizable marks for identification

15. Injury Inspection Penetrating wounds Non-penetrating wounds • caused by bullets, knives, bombs, etc. • - full extent of these wounds requires more than visual examination - caused by blunt force trauma, hand/finger impressions, burns, needle marks

16. Injury Inspection cont… • Penetrating wounds such as those caused by bullets draw special attention - presence of gunpowder around wound - long range bullet wounds result in a hole with no other surface information - shots held to the skin give a hole & “rim burn” - short range shot may singe body hair and leave similar marks as a skin-held shot but no burn mark - inches to feet away shots leave “stippling” marks

17. Injury Inspection cont… • Bullet wound can change shape because skin is elastic so gun caliber cannot always be estimated • Gunshot entry wounds are usually smaller than exit wounds • Bullets that hit bone often leave a star pattern on bone surface • Knife wounds are three dimensional; recognizable by experienced examiners without casting; most are by kitchen ware

18. Injury Inspection cont… • Non-penetrating wounds - blunt-force trauma leaves marks - hand & finger impressions on skin are measured for finger span and size - bite marks can be photographed and cast made - burns; frost bite; rope marks from hangings appear with an upward angle (fake ones have a horiz. line) - needle marks indicate drug use

19. Internal Inspection (Autopsy) • Most dissections begin with a “Y” incision over the torso • One cut - arc across chest from shoulder to shoulder • Second cut - long cut that extends from base of the breast bone to the pubic bone (curves around navel)

20. Internal Inspection (Autopsy) cont… • Organs are removed from the top down; each is massed out on a scale • Rib cutters and spreaders open the chest • Lungs are examined for damage and heart tissue will be sampled

21. Internal Inspection (Autopsy) cont… • Throat, esophagus, trachea, and upper spine examined; broken hyoid bone indicates strangulation • Stomach contents are examined and help determine time of death; tie victim to a specific place & time; intestines examined as well • Liver, spleen, & pancreas are sectioned for histology & drug presence

22. Internal Inspection (Autopsy) cont… • Bladder sample taken (urine) for testing of drugs • Presence of blood in urine can mean blunt force trauma over the kidneys • Women are examined for pregnancy, sexual interference, & semen • Once the internal examination is complete, the organs are replaced inside the body & the body is sewn up

23. Internal Inspection (Autopsy) cont… • Head is examined last; eyes are first • Hemorrhages to the eyes or lids (petechiae) indicate lack of circulation to the head (strangulation) • Single incision made - arch from one ear, over forehead, to other ear; face is flipped forward • Face area is examined for bruising beneath the skin • Skull is opened with a saw; brain examined and weighed

24. Other Autopsy Facts • Exhumations - body that has been buried is dug up for examination • Partial bodies/Amputations - ME sometimes must “reconstruct” a victim from their body parts - body parts can sometimes help police reconstruct the crime or profile the killer

25. Presentation to Other Experts • Medical examiners are NOT expected to see EVERY trauma ever inflicted on a victim • ME must rely on histology, toxicology, and other fields to help with cause of death ex. Scuba deaths, animal bites, pharmacy

26. Reconciliation of All Exhibits • Prior to the completion of the autopsy, all samples, reports, and exhibits are accounted for and checked for accuracy • All evidence (ex. bullets) is returned

27. Presentation of Findings • Final presentation is the autopsy report • Describes all findings, steps taken, and opinion of the examiner on the cause, method, and manner of death

28. Forensic Odontology • Definition: the application of dental science to help identify individuals and the study of teeth in bite mark analysis • Job title: Forensic odontologist

29. Identifying Remains • Victims can be identified by using a complete jaw, fragment of a jaw, or even just a few teeth • Dental x-rays best source for identification • Show relative positions of teeth, fillings, and other materials contained in the tooth • Forensic odontologist may also assist in the autopsy (take notes on teeth and cranial features) • Police use these dental findings, enter them into a computer and look for a close comparison

30. Example of Dental filling

31. Identifying Unknown Remains cont. • Often called to mass disaster sites (such as airplane crashes, fires, bombings, terrorist attacks, etc.) • May be called to mass graves after political crimes of massacres have been committed (ex. Rwanda and Guatemala)

32. Analyzing Bite marks • Criminals (and victims) sometimes leave bite marks • Can link a suspect to a victim and vice versa • Dental impressions often left in food too (chewing gum; also a good DNA sample)

33. Computer Imaging with Dental Records • Computer imaging technology can generate an outline of teeth • It is laid over top a digital photograph of the human bite mark on the victim • Called “compound overlay”

34. Computer Imaging continued • Image can be zoomed in for a close up • Look at edges of suspect’s teeth and compared with the injury pattern • In court, forensic odontologist would then testify to the strong association between the victim’s injury marks and the dental impressions of the suspect

35. How to Become a Forensic Odontologist? • First become a dentist • Need bachelor of science degree • Go to dental school (Doctor of Dental Science) • Gain experience in the field of dentistry • Take courses on forensic odontology supported by the American Board of Forensic Odontology