Human RemainsHuman Remains

The Postmortem Interval: Determining the Time of Death

The Postmortem Interval: Determining the Time of Death

• Pathologist usually determines

• Done most accurately within the first 24 hrs of death

• Pathologist usually determines

• Done most accurately within the first 24 hrs of death

Algor mortisAlgor mortis

• Cooling rate of the body after death

• Glaister formula– H=(98°F-internal temperature)/1.5– Body generally cools 1 to 1.5 degrees

per hour until it reaches environmental temp.

• Cooling rate of the body after death

• Glaister formula– H=(98°F-internal temperature)/1.5– Body generally cools 1 to 1.5 degrees

per hour until it reaches environmental temp.

• Factors to consider– Temp. of environment– Type of clothing– Clothing wet or dry– Air movement– Layers of clothing– Surface area to body mass

• Factors to consider– Temp. of environment– Type of clothing– Clothing wet or dry– Air movement– Layers of clothing– Surface area to body mass

Livor MortisLivor Mortis• Pooling of blood after the heart stops,

caused by gravity• Can indicate the position of the body at the

time of death• None found in areas of the body that touch

the ground• Begins within ½ hr after death• After 12 hrs discoloration will not move

• Pooling of blood after the heart stops, caused by gravity

• Can indicate the position of the body at the time of death

• None found in areas of the body that touch the ground

• Begins within ½ hr after death• After 12 hrs discoloration will not move

Rigor MortisRigor MortisRigor MortisRigor Mortis• Rigidity of the skeletal muscles after death

due to buildup of calcium ions• Occurs within 2 or 3 hrs after death• Gone within 30 hrs when muscle protein

begins decomposing• Affected by temp., dehydration, condition of

muscles, and use prior to death

• Rigidity of the skeletal muscles after death due to buildup of calcium ions

• Occurs within 2 or 3 hrs after death• Gone within 30 hrs when muscle protein

begins decomposing• Affected by temp., dehydration, condition of

muscles, and use prior to death

DecompositionDecomposition

• Gradual breakdown of dead organic matter which releases elements and compounds

• Caused by bacteria and fungi

• autolysis occurs as well

• Gradual breakdown of dead organic matter which releases elements and compounds

• Caused by bacteria and fungi

• autolysis occurs as well

Stages of decompositionStages of decomposition

1. Fresh

2. Initial decay

3. Putrefaction

1. Fresh

2. Initial decay

3. Putrefaction

4.4. Black putrefactionBlack putrefaction

5.5. Butyric Butyric fermentationfermentation

6.6. Dry decayDry decay

4.4. Black putrefactionBlack putrefaction

5.5. Butyric Butyric fermentationfermentation

6.6. Dry decayDry decay

Rate of decompositionRate of decomposition

• Dependent on environmental factors

• Fastest in warm, humid areas

• Slowest in cold, arid areas

• Results in either skeletonization or mummification

• Dependent on environmental factors

• Fastest in warm, humid areas

• Slowest in cold, arid areas

• Results in either skeletonization or mummification

Forensic AnthropologyForensic Anthropology

• Anthropology – study of humankind including anatomy, variability, evolution, and culture

• Forensic anthropology – specializes in the human skeletal system and its changes and variations, for purposes of legal inquiry

• Anthropology – study of humankind including anatomy, variability, evolution, and culture

• Forensic anthropology – specializes in the human skeletal system and its changes and variations, for purposes of legal inquiry

• Bodies are decomposed, badly burned, or mummified

• Identification of crime victims

• Cause of death

• Time of death (approx.)

• Demographics

• Bodies are decomposed, badly burned, or mummified

• Identification of crime victims

• Cause of death

• Time of death (approx.)

• Demographics

Human vs. Animal BonesHuman vs. Animal Bones

• Osteology – study of bones• Can be determined by visual

inspection• Can be determined through

microscopic examination (osteons irregular pattern in humans)

• Osteology – study of bones• Can be determined by visual

inspection• Can be determined through

microscopic examination (osteons irregular pattern in humans)

The SkeletonThe Skeleton

• Adult human has 206 bones

• Classified as long (arms), short (wrist), flat (scapula), or irregular (vertebrae)

• Adult human has 206 bones

• Classified as long (arms), short (wrist), flat (scapula), or irregular (vertebrae)

Estimating Height Using Long BonesEstimating Height Using Long Bones

• See page 275• See page 275

Sex DeterminationSex Determination• Most obvious differences in pubis, sacrum,

and ilium• Also shape of skull and mandible and size

of occipital prtuberance• Size of bones• Sacrum is straighter in females• Space in middle of pelvic bone is larger in

women

• Most obvious differences in pubis, sacrum, and ilium

• Also shape of skull and mandible and size of occipital prtuberance

• Size of bones• Sacrum is straighter in females• Space in middle of pelvic bone is larger in

women

Characteristics of Pubic BoneCharacteristics of Pubic Bone

• Width of arch (larger in fem)

• Width of body (wider in fem)

• Existence of well-defined ventral arc (not present in male)

• Width of arch (larger in fem)

• Width of body (wider in fem)

• Existence of well-defined ventral arc (not present in male)

Determining Sex Using Skull Features

Determining Sex Using Skull Features

• Angle of mandible

• Space at between mandible attachment

• Size of cranial bones

• Angle of mandible

• Space at between mandible attachment

• Size of cranial bones

Determining Agepage 281

Determining Agepage 281

• Teeth erupting, bones growing

• Closure of cranial sutures

• Changes in epiphyses

• Teeth erupting, bones growing

• Closure of cranial sutures

• Changes in epiphyses

Age based on cranial suturesAge based on cranial sutures

• Sagittal• Coronal • Lambodial

• Sagittal• Coronal • Lambodial

• Sagittal completely closed

– Male 26 or older– Female 28 or older

• Sagittal completely closed

– Male 26 or older– Female 28 or older

• All three major sutures completely closed

– Male 35 or older– Female 50 or older

• All three major sutures completely closed

– Male 35 or older– Female 50 or older

Age based on pubic boneAge based on pubic bone

• Pattern on symphysis– regular rows or furrows in younger

individuals– smooth with an oval surface– Breakdown of the bone in older

individuals

• Pattern on symphysis– regular rows or furrows in younger

individuals– smooth with an oval surface– Breakdown of the bone in older

individuals

Determining of Racep. 286-287

Determining of Racep. 286-287

• Caucasoid – European, Middle Eastern, East Indian

• Negroid– African, Aborigine, Melanesian

• Mongoloids– Asian, Native American, Polynesian

• Caucasoid – European, Middle Eastern, East Indian

• Negroid– African, Aborigine, Melanesian

• Mongoloids– Asian, Native American, Polynesian

CaucasoidCaucasoid

• Long, narrow nasal aperture

• Triangular palate

• Oval orbits

• Narrow zygomatic arches

• Narrow mandibles

• Long, narrow nasal aperture

• Triangular palate

• Oval orbits

• Narrow zygomatic arches

• Narrow mandibles

NegroidNegroid

• Wide nasal aperture• Rectangular palate• Square orbits• More pronounced zygomatic arches• Long bones are longer, less curvature,

greater density

• Wide nasal aperture• Rectangular palate• Square orbits• More pronounced zygomatic arches• Long bones are longer, less curvature,

greater density

MongoloidMongoloid

• More rounded nasal aperture

• Parabolic palate

• Rounded orbits

• Wide zygomatic arches

• More pointed mandibles

• More rounded nasal aperture

• Parabolic palate

• Rounded orbits

• Wide zygomatic arches

• More pointed mandibles

Facial ReconstructionFacial Reconstruction

• Uses standard tissue thickness and facial muscles to build a new face on a skull

• Not completely accurate, but has proven helpful

• Uses standard tissue thickness and facial muscles to build a new face on a skull

• Not completely accurate, but has proven helpful

Steps in facial reconstructionSteps in facial reconstruction• Establish gender,

age, race• Glue markers on skull

for tissue thickness• Mark muscle insertion

points

• Establish gender, age, race

• Glue markers on skull for tissue thickness

• Mark muscle insertion points

• Mount eyes in sockets

• Apply clay • Determine nose and

mouth thickness and width

• Cover the skull with layers of skin and add detail

• Mount eyes in sockets

• Apply clay • Determine nose and

mouth thickness and width

• Cover the skull with layers of skin and add detail

After reconstructionAfter reconstruction

• Photographs distributed

• Skull-photo superimpositions

• Proportion most important

• Photographs distributed

• Skull-photo superimpositions

• Proportion most important

Cause of deathCause of death

• Stab wounds

• Bullet holes

• Blows to the head

• Tool mark

• Stab wounds

• Bullet holes

• Blows to the head

• Tool mark

Bone AnomaliesBone Anomalies

• Healed breaks or fractures

• Joint replacements

• Osteoporosis

• Arthritis

• Healed breaks or fractures

• Joint replacements

• Osteoporosis

• Arthritis

Classwork/HomeworkClasswork/Homework

• Page 289-290 #2-18 even only!!

• Write questions and answers

• Page 289-290 #2-18 even only!!

• Write questions and answers