Forensic Anthropology



Forensic Anthropology

Skeletal Anatomy(300 bones born-206 as an adult)

Bones tell us a lot about a person:

How a person lived

Illnesses-healed fx,osteoporosis,polio,curvature of spine

Lf. vs rt. handed

Clues to occupation

Age of person at time of death

Sex of person

Race

Height

Distinguish between human and animal

Manner of death-homicide,suicide,natural, accidental or unknown

How many individuals are represented

What was the SEX?

Male skeleton

• Man’s bone weigh ~12 lbs

• Pelvic bone is narrow

• Thicker skull, heavier and bigger

• Tend to have a bony supraorbital ridge

• Low slanted forehead

• Smooth upper eye rim

• Subpubic angle is less than 90 degrees

• Prominent nuchal crest-nape of neck/skull

• Thicker and longer leg and arm bones

• Male bones grow until 20-21 years old-

• Parkman’s jaw=prominent, jutting jaw, more angulated

•

Female skeleton

• Women’s bones weigh~10lbs

• Skull is thinner and not as heavy

• Rounded forehead

• Sharpened around supraorbital ridge

• Pelvis is wider-to accommodate child birth

• Subpubic angle is more than 90 degrees

• Pubic bones separate to allow additional room for the baby’s head and will leave a small indention/depression on the bones after the delivery of the 2nd child

What was the persons RACE?

• Africans and descendants -smooth elongated skull with wide broad nasal bone; distance between orbits is wide and; the bone between the bottom of the nose and the upper teeth projects forward

• Europeans-Caucasoid- rough and elongate skull;narrow and long nasal bones;distance between the orbits is narrow;projecting chins

• Australian aborigines and Pacific Islanders have a rounded, receding jaw.

• People of Hawaiian descent have a distinctive-shaped jaw. called rocker jaw-(when the mandible is placed on a table and gently tapped it will rock like a rocking chair b/c rounded jaw.

• Native Indians-flat cheek and nasal bones,rounded skull,b/c they practiced using cradleboards to carry babies,the board molded and flattened the head.

• Puerto Ricans-put tight crocheted caps on the infants to protect them from bad influences and that shapes the head

Because of mixed racial heritage it is more difficult now-depend on computers

Pencil test is done in the field to give police quick head start

Pencil test 1. attempts to touch one end of the pencil to

chin while touching the other end to the

nasal opening. If the pencil lies flat and

touches both points at the same time it

caucasoid. If it does not lie flat because of

the mouth section, it is prob. Africanoid

b/c of the way the teeth section protrude.

Pencil test 2. Nasal tilt-that little bit of bone at the base

of the nose between the nostril. by

running the pencil gently up into the

nasal opening, the pencil will be stopped

from entering the nasal opening b/c of

the tiny ridge there. If it is Africanoid, the

pencil will enter the nasal opening easily.

Pencil test 3. by laying the skull face up in the palm-the

pencil can be balanced across the nasal

opening. If a finger can be slid between

cheekbone and pencil without knocking

pencil off-caucasoid. Difficult to do on

asian b/c face is flatter rather than

pointy.

What was the HEIGHT?

No prob.when skeleton is intact. but with dismemberment

Mathematical formula by Dr.Mildred Trotter

Application mainly used in disasters-planes and Twin towers

Measured on osteometric board:

Length of femur x 2.38 + 61.41cm = height

Length of femur x 2.52 + 78.62 cm =height

Length of fibula x 2.68 + 71.78 cm = height

Convert to inches-feet

Femur of female 473mm. approx 68 inches tall or 5’8”

47.3cm x 2.38=112.574 add 61.41cm = 173.98cm divide by 2.54cm = 68 inches= 5’8” .

Age at time of death

based on how skeletal is formed- bones do not grow all in one piece. epipysis form separately from the diapnysis and fuse together and become hard bone is ossification. there are 450 centers of ossification that fuse. You can actually see how the bones fuse by holding the bones up to a light;if there is a slight glow throught the bones then they haven’t fused yet. if not light then they are fused. Table when each bone fuses in the body-

elbow 14

hands and feet 15

ankle 16

femur 17

knee 18

wrist 19

shoulder 20

crest of illium 21

clavicle 28

Sutures in skull form at different ages-sagittal suture by 35 and the coronal by 40.

Cut a small wafer of long bone and count the circles formed around the canal. formula for that also

Aging process

Osteoporosis-leaves the bones thinner, porous and susceptible to fx. by 55 lost 30% bone

Examine teeth-later on

What the person left handed or right handed?

Ball and socket joint is affect-with regular use the socket becomes beveled and a slight grove forms.

Lefty will have more beveling in the left shoulder socket

The dominant arm will be a few millimeters longer to compensate for the more work it does.

Occupation?

With over usage, bone and processes accommodate for over usage of muscle in that area. they will be more prominent. Waitress-left deltoid

High heels and cowboys strong calf muscles-

ridges in tibia

Manner of death?

Blows to head-bullet holes-force and angle of blows

Most cases the cause of death is apparent and gruesome.

Falling down stairs-evidence to support it

Autopsy is critical. body tissue & fluids:sampled,analyzed

Depressed fx-moving object caused the blow

Broken bones heal in a few months.New bone shows shiny rounded edges & xray reveals fine line where fx was. Dead bones don’t grow nor heal!

Knife-parallel cuts marks,shape of the edge of blade on bone

Gnawing-markings of rodent

Mower-destroy the bone

Mattock/axe & cut off in car door-clean cut

Circular saw-curved lines

Saber saw –regular straight cuts

Handsaw-irregular straight cuts

Serrated knives-scalloped-edged cut

Dull objects- U shaped depression

Sharp objects make a V shaped notch

Bones burn but not all the way-

body lying face up-smoke inhalation

body lying face down-dead prior to fire

Strangled-bone in throat will be fx

Poison-extracted from bone years later

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