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ANTH 6 - Forensic Anthropology
Ancestry

 LAB PRACTICUM 

1.  CRANIAL INDEX:  Use the spreading caliper.  Measure the maximum breadth of the skull from Euryon (eu) to Euryon (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 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.

4.  TOTAL FACIAL INDEX:  Use The sliding caliper to measure the maximum height of the face from Nasion (n) to Gnathion (gn).  Use the spreading caliper to measure the maximum width of the face from Zygion (zy) to Zygion (zy).  Divide the facial height by the facial width and multiply by 100.

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 (o) and Opisthocranion (op).

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 [in the regions lateral to Glabella (g)] 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.   there are a wide variety of so-called Wormian bones. they are sometimes classed as “extra-sutural” bones.  Different names sometimes are assigned depending on the suture where these tiny “islands of bone” are located.   If these bones are particularly large they may have names, such as the “Inca bone.”

11.  EYE ORBIT SHAPE:  Examine 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 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 nasal breadth by the nasal height and multiply by 100. 

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.  Note the shape of the sutures. Look for displacements possibly due to ante-mortem fractures.  From the anterior view, check the width of the bones and whether or not they expand outward from superior to inferior.  While in the lateral view, check if the bones arch downward (convex) or up (concave).  

16.  NASAL OVERGROWth:  Examine the nasal bones in lateral view.  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 … resting against the bone of the maxilla just below the nasal opening, try to run the pencil … gently into the nasal opening.  In Caucasoids there is usually a dam (nasal sill) that will stop the … pencil.  In Negroid skulls there is no dam or nasal sill, and the pen[cil] easily will glide into the nasal aperture.  Mongoloid skulls will range between these two extremes" (Bass 1986:83).  Be extremely careful when inserting a pencil into the nasal cavity to avoid bone damage.  Be warned the description may be confusing unless you’ve seen this demonstrated.

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 your hand 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 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).  Again, you may need to see this one demonstrated.

20.  EXTERNAL AUDITORY MEATUS.  Holding the skull in lateral views, examine the overall shape of the external auditory meatus.  Using a good small flashlight, attempt to observe the oval window deep within the auditory canal.  If present, it is usually a Caucasoid trait.  Note any evidence of exostoses.

21.  PALATE SHAPE:  Holding the skull in inferior view, examine the palate area, which includes the maxillae and palatines. Note any evidence of palatine tori or evidence of exostosis.  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.  Note if the suture is “raised.” Describe the shape.  

23.  OCCLUSION:  Holding the skull in lateral view, examine the occlusion of the 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 on the lateral and mesial borders.

25.  ASCENDING RAMUS OF MANDIBLE:  Holding the mandible in lateral view, examine the overall shape of the ascending ramus.

26.  GONIAL ANGLE:  Holding the mandible in anterior view, examine the gonial angle to see if it is rounded or outward flaring.

27.  CHIN:  Holding the mandible in lateral view, examine the relative projection of the chin.


 TABLE 1: Cranial Ancestral Traits:  A Summary of the Current Research Methodology

TRAIT CAUCASOID NEGROID MONGOLOID
1. cranial index* 75 to 80, mesocranic less than 75, dolichocranic greater than 80, brachycranic
2. sagittal contour arched flat with bregmatic or post-bregmatic depression arched
3. keeling of skull vault absent present absent
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 profile orthognathic (straight, flat) prognathic (projecting), especially in the alveolar area intermediate to mostly orthognathic
6. nuchal ridge profile pinched and prominent slightly pinched rounded
7. base chord long long short
8. suture pattern simple simple complex
9. metopic suture present absent absent
10. Wormian bones absent absent Present
11. eye orbit shape angular and sloping square or rectangle rounded and non-sloping
12. lower eye border receding receding projecting

13. nasal index*

less than 48, leptorrhinic (narrow)

greater than 53, platyrrhinic (wide)

48 to 53, mesorrhinic (intermediate)

14. nasal cavity shape

tear shaped

rounded and wide

oval shaped

15. nasal bones

"tower shaped," narrow and parallel from anterior, slightly arched in profile

"Quonset hut shaped," wide and expanding from anterior, no arch in profile

"tented," narrow and expanding from anterior, arched in profile

16. nasal overgrowth

absent

absent

present

17. nasal sill or dam

present

absent

absent

18. lower nasal spine

large and sharp

small

small

19. zygomatic arches

narrow and retreating

medium to large and retreating

projecting

20. external auditory meati

round

oval window

round

oval

21. palate shape

triangular

rectangular

parabolic or horseshoe shaped

22. palate suture

irregular

irregular

straight

23. occlusion

slight overbite

slight overbite

edge-to-edge or even

24. central incisors

blade shaped

blade shaped

shovel shaped

25. ascending ramus of mandible

pinched at midsection

back slanted

wide and vertical

26. gonial angle

slightly flared

not flared

slightly flared

27. chin profile

prominent and projecting

rounded

slightly projecting


Nota bene:  Some of you may this interesting.

Gill, George W. and Rhine, Stanley, eds.

               1990 Skeletal Attribution of Race: Methods for Forensic Anthropology. Maxwell Museum of Anthropology, Anthropological Papers No. 4 (Albuquerque, NM).

This is considered a “gotta-have” book in good upper-division and graduate-level forensic anthropology classes.  Copies are difficult to find at times. Luckily, the edition is back in print.  I don't remember the tile being particularly costly (less than $20.00). To place an order, contact the UNM Press order department directly at (505) 277-4810.   http://www.unm.edu/~maxwell/


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April Garwin
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