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Death: Meaning, Manner, Mechanism, Cause, and Time & Forensic Anthropology.

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Presentation on theme: "Death: Meaning, Manner, Mechanism, Cause, and Time & Forensic Anthropology."— Presentation transcript:

1 Death: Meaning, Manner, Mechanism, Cause, and Time & Forensic Anthropology

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3 Time After Death EventAppearanceCircumstances 2 – 6 hoursRigor beginsBody becomes stiff and stiffness moves down body Stiffness begins with the eyelids and jaw muscles after about 2 hours, then center of the body stiffens, then arms and legs 12 hoursRigor complete Peak rigor is exhibited Entire body is rigid 15 – 36 hours Slow loss of rigor Loss of rigor in small muscles first, followed by larger muscles Rigor lost first in head and neck, and last in bigger leg muscles 36 – 48 hours Rigor totally disappears Muscles become relaxed Many variables can extend rigor beyond the normal 36 hours Progression of Rigor Mortis

4 FactorsEventEffectCircumstances TemperatureCold temperature Inhibits rigorSlower onset and slower progression of rigor Warm temperature Accelerates rigor Faster onset and faster progression of rigor Activity before death Aerobic exercise Accelerates rigor Lack of oxygen to muscles, the build up of lactic acid, and higher body temperature accelerates rigor SleepSlows rigorMuscles fully oxygenated will exhibit rigor more slowly Body weightObeseSlows rigorFat stores oxygen ThinAccelerates rigor Body loses oxygen quickly and body heats faster Factors Affecting Rigor Mortis

5 StageWhat Happens During Decomposition Initial decayCorpse appears normal on the outside, but is starting to decompose from the actions of bacteria and autolysis. PutrefactionOdor of decaying flesh is present and the corpse appears swollen. Black putrefactionVery strong odor. Parts of the flesh appear black. Gases escape and the corpse collapses. Butyric putrefactionCorpse is beginning to dry out. Most of the flesh is gone. Dry decayCorpse is almost dry. Further decay is very slow from lack of moisture. Stages of Decomposition

6 Third-stage larva has three slits (4-5 days old) First stage larva Second stage larva Third stage larva

7 StageSize (mm)ColorWhen First Appears Duration in Phase Characteristics Egg2WhiteSoon after death 8 hoursFound in warm, moist areas of the body like the eyes and mouth Larva 15White1.8 days20 hoursBlack mouth hooks visible; thin body; 1 spiracle slit near anus Larva 210White2.5 days15-20 hours Black mouth hooks; actively feeding; 2 spiracle slits Larva 317White4.5 days36-56 hours Black mouth hooks; fat body; 3 spiracle slits Blowfly Life Cycle

8 StageSize (mm)ColorWhen First Appears Duration in Phase Characteristics Pre- pupa 9Light brown 8-12 days hours Larva migrates away from the body and to a dry area Early and late pupa 9Light brown; changes to dark brown days6-12 daysImmobile; does not feed; changes to dark brown with age; pupa case splits open prior to adult emerging AdultVariesBlack or green daysSeveral weeks Incapable of flight for the first few hours Blowfly Life Cycle, Continued

9 Eggs Larva 1 Larva 2 Larva 3 Pupa Adult 8 h 20 h h h 6-12 d

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13 As the bones develop, a membrane (the periosteum) forms on the surface of the bones This membrane contains nerves and blood vessels, and also functions in keeping bones moist and repairing injuries

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22 The sagittal suture is closed by about age 32 The lamboidal suture is closed by about age 30

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