Western Kentucky University

7/30/2019 Western Kentucky University

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WESTERN KENTUCKY UNIVERSITY

Anth 300 Forensic Anthropology

Dr. Darlene Applegate

Spring 2008Lab 9: Race Determination

INTRODUCTION

The analytical stage of forensic anthropology involves answering questions that

lead to identification of the individual whose remains are being examined. The

questions asked in developing a biological or demographic profile for an

individual include the following:

What is the race of the individual? What is the sex of the individual?

What is the age of the individual?

What is the stature of the individual?

What pathologies did the individual have?

What traumas did the individual have?

What idiosyncratic traits did the individual have?

In this lab, we will examine the first of these questions: race determination.

OBJECTIVES

To learn how to use anthropometric measuring instruments.

To recognize and assess skeletal indicators of race.

To practice carefully handling skeletal material.

READINGS

Review the lecture notes and handouts on race determination.

Review Chapter 7 of the Byers text and Byers lab manual.

TERMS


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biological (demographic) profile

osteometry

anthroposcopy

metric trait

nonmetric trait

sliding caliper

spreading caliper

osteometric board

dorsal/anterior

ventral/posterior

proximal

distal

superior

inferior

race ancestry

Mongoloid

Negroid

Caucasoid

USING OSTEOMETRIC MEASURING DEVICES

You will be using several osteometric measuring devices to complete this

lab. Carefully follow the directions for using these devices to insure thatinstruments and bones are not damaged. Osteometric equipment is expensive

because of the precision with which they are manufactured; special care in

using the equipment must be exercised at all times. All measurements must be

made in metric units. Ask for help reading the instruments, if needed.

Sliding Caliper

The sliding caliper is used to make linear measurements on bones. We are

using manual calipers and digital sliding calipers that run on batteries. Each

student should practice using both types of calipers. The level of accuracy is

0.1 mm for the manual and digital calipers.

MANUAL SLIDING CALIPER

1. Depress and hold the release button on the bottom part of the caliper.

2. Slide the right half of the caliper to the right to open it up. Open it

beyond the size of the bone being measured.


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3. Place the bone between the two lower pinchers.

4. Gently slide the right half of the caliper back to the left to close the

lower pinchers against the edges of the bone. Be very careful!

5. Read the measurement from the top line of measures. (Metric along the

top, English along the bottom.) The numbers correspond to centimeters.

The tick lines between the numbers correspond to millimeters. Select

the closest millimeter reading without going over. The small scale is for

tenths of a millimeter; find the number along this scale that best lines up

with a number of the main centimeters scale. Your answer should read,

for example, 2.35 cm.

6. Depress and hold the release button and slide the right half of the caliper

to the right again to open it up.

7. Remove the bone from the caliper.

8. Close the caliper.

9. Multiply your answer by 10 to convert to millimeters. In our example,

your final answer would be 23.5 mm.

10.Record your measurement in millimeters.

11.Repeat these steps for the next measurement.

DIGITAL SLIDING CALIPER

1. Close the caliper completely.

2. Press the ON/ZERO button to turn on the caliper.

3. Make sure the caliper is set on metric (millimeters) instead of English

(inches). Press the MM/IN button to change from English to metric if

needed.

4. Press the ON/ZERO again to reset the caliper to zero.

5. Slide the right half of the caliper to the right to open it up. Open it

beyond the size of the bone being measured.

6. Gently slide the right half of the caliper back to the left to close it against

the edge of the bone. Be very careful!

7. Read the measurement, which is expressed as 000.0 mm.

8. Slide the right half of the caliper to the right again to open it up.

9. Remove the bone from the caliper.10.Close the caliper.


12.Repeat steps 4-11 for the next measurement.

13.Press the OFF button when you are done measuring.

Spreading Caliper


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The spreading caliper is used to make linear measurements around the

protrusions on the skull. The level of accuracy is 1 mm but you can estimate to

0.1 mm.

1. Rest the skull on a cushioned surface, or have your lab partner hold the

skull securely.2. Place one end of the spreading caliper on the first bone landmark,

supporting the end of the caliper with your finger if needed.

3. Spread open the other end of the spreading caliper.

4. Place the other end of the spreading caliper on the second bone

landmark, supporting the end of the caliper with your finger if needed.

5. Read the measurement. The numbers on the scale are centimeters, and

the tick lines between the numbers are millimeters. You'll have to

estimate the measurement of tenths of a millimeter. For example, 35.73

cm might be the reading.

6. Open the spreading caliper away from the bone landmarks.

7. Remove the spreading caliper.

8. Close the spreading caliper.

9. Multiply your answer by 10 to convert to millimeters. In our example,

your final answer would be 357.3 mm.


11.Repeat the steps for the next measurement.

GENERAL INSTRUCTIONS

Carefully handle the instructional casts and bones laid out in the lab, being sure

to keep the bones with their labels. Some of the ends of the bones where you

will be making measurements are very delicate and will degrade if handled

improperly. Keep the materials on the bubble wrap to cushion them from the

hard table surfaces, and wear gloves when working with real bones.

Record your responses to the questions in pencilon the answer sheet provided

in the lab.

Work as a small group with the skulls, since we have a limited number of

skulls. Each group will be given a time limit with each skull specimen.

When working in a group, it is essential that allgroup members look at the

bones and make the measurements.


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Use reference books in the lab as needed. Ask the instructor or assistant if you

don't understand something.

The lab is due on Thursday, March 27 at the beginning of class. Late labs

will not be accepted.

RACE DETERMINATION

Patterns of geographic variation of the human skeleton are used to identify the

race or ancestry of an individual. Most forensic anthropologists use a three-

race model that includes Mongoloid, Negroid, and Caucasoid races. Native

Americans are typically included in the Mongoloid race.

Compared to sex, age, and stature estimation, race determination is "more

difficult, less precise, and less reliable" because "no human skeletal markers ...correspond perfectly to geographic origin" (White 1991:328-329). In addition,

many skeletal indicators used to estimate race are nonmetric traits, whose

documentation through anthroposcopic methods can be somewhat subjective,

varying for researcher to researcher. However, race estimation is a critical

endeavor in forensic identification as sex, age, and stature estimation are

greatly influenced the race of the individual.

Skeletal indicators of race focus primarily on skull and dental traits. Racial

indicators on the skull are both nonmetric and metric traits and include

robusticity, lengths and widths of skull features, shapes of skull features, andunique population-specific dental features.

The Giles-Elliott method is a quantitative means of estimating race based on

the skull, but we will not be using this approach for our lab assignment; this

method will be demonstrated if you undertake research with the instructor at a

future date. Postcranial skeletal elements used in race estimation include the

femur, tibia, coxa, scapula, rib, and calcaneus. In this lab, however, we will be

examining only skull racial indicators.

The following drawings illustrate some of the skull differences among the threemajor human races.


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Caucasoid skull drawings (left from Bass 1986:84, right from France

2003:239).


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Negroid skull drawings (left from Bass 1986:85, right from France

2003:238).


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Mongoloid skull drawings (left from Bass 1986:86, right from Franc

e 2003:240

The following table summarizes typical expressions of 28 metric and nonmetric

skull traits for the three human races. A guide to assessing these traits follows

the table.

TRAIT CAUCASOID NEGROID MONGOLOID

1. cranial index 75 to 80, mesocranicless than 75,

dolicocranic

greater than 80,

brachycranic

2. sagittal

contourarched

flat with bregmatic orpost-bregmatic

depression

arched

3. keeling of

skull vaultabsent absent present

4. total facial

index

greater than 90, narrow

to very narrow

less than 85, broad to

very broad

85 to 90, medium or

average

5. facial profileorthognathic (straight,

flat)

prognathic (projecting),

especially in the

alveolar area

intermediate to mostly

orthognathic

6. nuchal ridgeprofile

pinched and prominent slightly pinched rounded

7. base chord long long short

8. suture pattern simple simple complex

9. metopic

suturepresent absent absent

10. wormianbones

absent absent present

11. eye orbit

shapeangular and sloping square or rectangle

rounded and non-

sloping

12. lower eye

border

receding receding projecting

13. nasal indexless than 48,leptorrhinic (narrow)

greater than 53,platyrrhinic (wide)

48 to 53, mesorrhinic(intermediate)

14. nasal cavity

shapetear shaped rounded and wide oval shaped

15. nasal bones "tower shaped," narrow

and parallel from

"Quonset hut

shaped," wide and

"tented," narrow and

expanding from


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anterior, slightly archedin profile

expanding fromanterior, no arch in

profile

anterior, arched inprofile

16. nasal

overgrowthabsent absent present

17. nasal sill or

dampresent absent absent

18. lower nasal

spinelarge and sharp small small

19. zygomatic

archesnarrow and retreating

medium to large and

retreatingprojecting

20. externalauditory meati

round round oval

21. palate shape triangular rectangular parabolic or horseshoe

shaped22. palate suture irregular irregular straight

23. occlusion slight overbite slight overbite edge-to-edge or even

24. central

incisorsblade shaped blade shaped shovel shaped

25. shape of

ascending ramusof mandible

pinched at midsection back slanted wide and vertical

26. projection of

ascending ramusof mandible

non-projecting projecting non-projecting

27. gonial angle slightly flared not flared slightly flared

28. chin profileprominent and

projectingrounded slightly projecting

1. CRANIAL INDEX: Use the spreading caliper. Measure the maximum

breadth of the skull from euryon (eu) to euyron (eu). Measure the length of the

skull from glabella (g) to opisthocranion (op). Divide the cranial breadth by the

cranial length and multiply by 100. (See figures below for landmarks.)

2. SAGITTAL CONTOUR: Holding the skull in profile, examine the contour

of the cranium along the sagittal suture.

3. KEELING OF SKULL VAULT: Holding the skull in anterior position,

examine the contour of the cranium. Keeling is a pinched appearance along the

sagittal suture.


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4. TOTAL FACIAL INDEX: Use the sliding caliper to measure the maximum

heighth of the face from nasion (n) to gnathion (gn). Use the spreading caliper

to measure the maximum width of the face from zygion to zygion (zy). Divide

the facial height by the facial width and multiply by 100. (See figures below

for landmarks.)

5. FACIAL PROFILE: Holding the skull in profile, gently "place one end of

your pencil on or near the anterior nasal spine (on the midline of the skull) at

the base of the nasal aperture [nasal cavity]. Lower the pencil toward the face

so that the pencil will touch the chin" (Bass 1987:87). If the pencil hits the

alveolar area of the mouth, the face is prognathic. If the pencil extends to the

chin, the face is orthognathic. "Caucasoids have a 'flat' (orthognathous) face in

the dental area along the midline. This is the opposite of the Negroid face,

which exhibits protrusion of the mouth region, known as prognathism. ...

Negroids are noted for alveolar prognathism, or an anterior protrusion, of the

mouth region. A pencil or ballpoint pen placed with one end on the nasal spine

(midline at base of nasal aperture) will not touch the chin (the teeth protrude

too far forward)" (Bass 1986:87).

6. NUCHAL RIDGE PROFILE: Holding the skull in profile, examine the

nuchal ridge and note the shape.

7. BASE CHORD: Holding the skull in inferior view, examine the distance

between opisthion and opisthocranion. Measure the distance using the linear

caliper.

8. SUTURE PATTERN: Examine the pattern of the cranial sutures (sagittal,

cornonal, squamosal, lambdoidal) and describe the pattern as simple (not very

convoluted) or complex (very convoluted).

9. METOPIC SUTURE: Examine the frontal bone superior to the nasal bones

for evidence of a short suture known as the metopic suture.

10. WORMIAN BONES: Examine the lambdoidal suture and look for small

bones within the suture line. These bones are called wormian bones.

11. EYE ORBIT SHAPE: Examine BOTH of the eye orbits from the anterior

view. Describe the overall shape as rounded or squared. If the eye orbits are

rounded, examine the top border to see if it is level or if it slopes laterally.

12. LOWER EYE BORDER. Examine the skull in profile, gently placing a

pencil vertically across the eye orbit. If the pencil is a vertical plane, then the


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lower eye border is projecting. If the pencil is not a vertical plane, then the

lower eye border is not projecting.

13. NASAL INDEX: Using the sliding caliper, measure the maximum breadth

of the nasal cavity (at right angles to the nasal height), from alare to alare (al).

Measure the nasal height from nasion (n) to nasospinale (ns). Divide the nasalbreadth by the nasal height and multiply by 100. (See figures below for

landmarks and measurement information.)

14. NASAL CAVITY SHAPE: Examine the overall shape of the nasal cavity

from the anterior view.

15. NASAL BONES: Examine the shape of the nasal bones from the anterior

and lateral views. From the anterior view, check the width of the bones and

whether or not they expand outward from superior to inferior. For the lateral

view, check if the bones arch downward (concave up).

16. NASAL OVERGROWTH: Examine the nasal bones from BOTH lateral

views. An overgrowth is present if the inferior ends of the nasal bones

overhang the superior edge of the nasal cavity.

17. NASAL SILL OR NASAL DAM: "Carefully observe the base of the nasal

aperture [nasal cavity or opening]. With your pencil or ballpoint pen resting

against the bone of the maxilla just below the nasal opening, try to run the

pencil or pen gently into the nasal opening. In Caucasoids there is usually a

dam (nasal sill) that will stop the pen or pencil. In Negroid skulls there is nodam or nasal sill, and the pen easily will glide into the nasal aperture.

Mongoloid skulls will range between these two extremes" (Bass 1986:83). Be

extremely careful when inserting a pen or pencil into the nasal cavity to avoid

bone damage. Be sure to check BOTH sides of the nasal cavity.

18. LOWER NASAL SPINE: Holding the skull in lateral view, examine the

lower nasal spine that extends from the inferior edge of the nasal cavity.

Describe the shape.

19. ZYGOMATIC ARCHES: "Hold the skull with the occipital region in yourhand and the facial area up. Place a pencil across the nasal aperture [nasal

cavity]. Now try to insert your index finger between the cheek (zygomatic)

bones and the pencil. Caucasoids have a face that comes to a point along the

midline and cheek bones that do not extend forward. This will allow you to

insert your finger between the cheek bones and the pencil without knocking the

pencil off. Mongoloids have a much flatter face (the cheek bones extending


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much further forward), and it is difficult to insert your finger between the

pencil and the cheek bones on a Mongoloid skull without knocking the pencil

off" (Bass 1986:83). Be sure to check BOTH zygomatic arches.

20. EXTERNAL AUDITORY MEATI: Holding the skull in lateral views,

examine the overall shapes of the external auditory meati. Be sure to checkBOTH external auditory meati.

21. PALATE SHAPE: Holding the skull in inferior view, examine the palate

area, which includes the maxillae and palatines. Describe the overall shape.

22. PALATE SUTURE: Holding the skull in inferior view, examine the

middle portion of the suture between the maxillae and palatines. Describe the

shape.

23. OCCLUSION: Holding the skull in lateral view, examine the occlusion ofthe upper and lower incisors. If the maxillary incisors are anterior relative to

the mandibular incisors, this is an overbite. If the maxillary and mandibular

incisors meet evenly, this is edge-to-edge occlusion.

24. CENTRAL INCISORS: Holding the mandible in superior view and/or the

maxillae in inferior view, examine the shape of the central incisors. Shovel-

shaped incisors have posterior-oriented projections.

25. SHAPE OF ASCENDING RAMUS OF MANDIBLE: Holding the

mandible in lateral view, examine the overall shape of the ascending ramus. Besure to check BOTH lateral views.

26. PROJECTION OF ASCENDING RAMUS OF MANDIBLE: Holding the

mandible in posterior view, examine the posterior edge of the ascending ramus.

If the bone projects toward the midline, the ascending ramus is projecting. If

the bone does not project toward the midline, the ascending ramus is non-

projecting.

27. GONIAL ANGLE: Holding the mandible in anterior view, examine

BOTH of the gonial angles to see if they are rounded or outward flaring.

28. CHIN: Holding the mandible in lateral view, examine the relative

projection of the chin.


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The metric measurements are based on skull landmarks that are illustrated in

the following drawings of the anterior, inferior, and lateral views of the skull

(Bass 1987:63-65). The skull landmarks you need to know and use for this lab

are: glabella (g), opisthocranion (op), opisthion (o), euryon (eu), nasion (n),

nasospinale (ns), alare (al), gnathion (gn), and zygion (zy).


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Assignment

Examine the four skulls labeled SKULL1, SKULL2, SKULL3, and SKULL4.

Compare them to the known skulls and figures in the reference materials.

On the answer sheet, circle all the skull characteristics that you observe, noting

that a trait may be present on one side of the skull but not the other (in other

words, check both sides!).

For the indices, you will also record the quantitative value (rounded to tenths

place) in the first column of the answer sheets.

If a bone is missing or broken such that the trait cannot be evaluated on either

side of the skull, mark the last column of the answer sheet for that particular

trait.

Using the three-race model, determine the most likely racial affiliation for each

specimen. If appropriate, use qualifying terms such as "probably" or "possibly"

if a specimen has a significant number of traits of more than one race, but select

the race with the largest number of traits.


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