Forensic Anthropology Exam 2

Bones of hips

Bones of hip are called os coxae with the ilieum, ischium and pubis.

Pelvic inlet and sex determination

if you have the entire pelvis (sacrum and os coxae) and look down onto top of pelvis the hole is the pelvic inlet. Oval shaped in females and compressed and heart shaped in males.

Complete fracture

two separate pieces

Morphology of the pubic symphyses and age determination

• 1920 Todd developed an aging system using morphological changes on the pubic symphysis. • Todd identified 10 phases • After age 50 the changes become irregular so there's a general category of 50 or older. • Identified 4 parts of pubic symphysis • Identified four different ways to describe the look of the symphysis • Over time margins of pubic symphysis become well defined, ossific nodules develop at top of bone and sometimes at bottom. At more advanced age you get bony outgrowth etc.

Methods for determining ancestry

• Anthroposcopic • Osteometric • Always general trend or tendency and always individual variation. Everything is a gradation and it's never simple.

Morphology of the skull vault and determining ancestry

• Cranial suture complexity • European and African ancestry have simple cranial sutures. Have lamboidal and sagittal sutures • In Asians there is much more complex suture morphology with extra bits of bones.

tooth wear and age determination

• Degree of ware on teeth on age • Diets today too soft to have substantial tooth wear so not that important in forensic work

manner of death

• Legal certification • The events or circumstances that led to death • Gunshot wound: accident, homicide, or suicide?

Sex determination

• Sex cannot be determined from bones of infants and children. Sex differences in skeleton don't start to appear until puberty. • Only way to reliably determine sex in subadults is through DNA analysis. • Also keep in mind that there's interpopulation difference in sex traits. So best to know ancestry before you start to determine sex. • Both males and females as you age get slightly larger and more robust with age. So in late ages this can skew sex determination.

Limitations on determining ancestry

• Skeleton of children are not diagnostic for ancestry except for some certain dental traits • Mixed ancestry can make determination a lot more difficult

Methods for Identifying Ancestry from the Skeleton

• Skull and dentition: Diagnostic • Postcranial skeleton: Less diagnostic

Direction of force

• Want to understand how force is being applied to bone • Different directions of force will cause different types of breaks.

How important is it to use the right formula for stature estimation?

• Will get a range of 2 and half inches. Kind of large. So want to use ancestry. • Formulae derived from lower limb bones are more accurate than those derived from the upper limb bones.

Limitations to determining cause of death

Again... forensic anthropologists must know their limitations • Forensic anthropologists just see the bone. They can't say for sure what happened in the soft tissue. • When commenting on bone trauma, the forensic anthropologist should say that the trauma is "consistent with" a certain cause of death • Important because there are just too many unknowns. E.g skull with gunshot wound. Would say that this would be consistent with death by gunshot. But the person could have been shot post mortem. • Limited to injuries to bone and teeth.

Stress vs strain of bone

Bone will bend, and bounce back, up to a point. This area is the elastic deformation. The next section of the strain and stress graph plastic deformation the bone will bend but it won't bounce back (happens at yield point) At the failure point the bone will break.

Tooth and palate in sex determination

Both tooth and palate size tend to be smaller in females and larger in males.

Skull and sex determination

Can use it to determine sex 80-90% of the time. [1] Size of skull [2] Forehead [3] Zygomatics [4] Tooth and palate size [5] Chin shape [6] Temporalis lines [7] Gonial eversion [8] Nuchal crest [9] Mastoid processes [10] supra-orbital margin [11] Supra-orbital ridge [12] Mental eminence

Potential pitfalls

Charts are male and female averages. Generally girls develop faster than boys but the sex of an individual can not be determined in a subadult. So the charts are an average between males and females this adds error. Precision of age estimates drop as age increases. At infancy error is plus or minus 2 months at 15 plus or minus 3 years. Usually look at bones using radiograph so you can see bones still erupting.

Zygomatics in sex determination

Check bones. Smaller in females than in males.

Mental eminence

Chin area. Projection of bone right at chin. Smooth in females and a little bump In males raised off of surface.

Supra-orbital ridge/glabella in sex determination

Entire brow ridge and glabella is point between eyebrow. Very smooth in females and prominent in males.

Forehead and sex determination

Forehead in males will be more slanted or sloping and in females it will be more vertical.

Dental development and eruption and age determination

Four development stages scored o Crown calcification o Root development o Eruption o Root closure

Medial aspect of the ischipubic ramis

Has sharp edge in females and in males this tends to be much more broad and round.

Size of skull in sex determination

Male skull will be larger and more robust than the females.

Gonial eversion and sex determination

Males tend to have more gonial eversion, which is a slight flaring of mandible on the sides. Women don't usually have this.

Temporalis lines in sex determination

Males tend to have more temporalis lines (muscle attachment lines) less pronounced in females.

Greater sciatic notch and sex determination

Notch tends to be wide in females and small in males. There is however population and individual variation. Scoring method developed by Walker.

Preauricular sulcus and sex determination

Often present in females and very rare in males. Groove along the antero-inferior edge of the auricular surface of the ilium

Nuchal crest and sex determination

On back of skull. Area tends to be smoother in females and more crestlike in males. hAs to do with muscles holding up the head.

Mastoid processes and sex determination

On temporal bones right behind ears. Larger in males and smaller in females.

Supra-orbital margin and sex determination

Outside edge of eye orbit. In females very sharp well-defined edge and much more rounded in males.

radiologic techniques and age determination

Resorption of trabeculae (radiographs): in general bone thins and becomes less dense.

Chin and sex determination

Rounded and narrow in females and in males the chin is more square.

Trauma analysis

Trauma analysis is the second most important issue in forensic anthropology (aftier biologic profile.

Subpubic concavity and sex determination

Turn os coxae and look at it from the side. Concave in females and straight in males.

Subpubic angle and sex determination

Where the os coxae come together. Wide in females and narrow in males.

Important features of the pelvis

[1] Greater sciatic notch [2] Preauricular sulcus [3] Pelvic inlet [4] Subpubic angle [5] Subpubic concavity [6] Medial aspect of the ischipubic ramis [7] Ventral arc

Anthroposcopic methods of determining ancestry

[1] Morphology of the nose [2] Morphology of the face [3] Morphology of the skull vault [4] Morphology of the jaw [5] Dental traits [6] Postcranial skeleton

5 Categories of manner of death

[1] Natural [2] Accidental [3] Homicide [4] Suicide [5] Unknown

Morphology of the nose in determining ancestry

[1] Openings [2] Lower border [3] Spine [4] Bridge [5] Root

5 different categories of force

[1] Tension [2] Compression [3] Torsion [4] Bending [5] Shearing

Infraction

bone breaks but there is some sort of connection between the two pieces

Fracture line

isn't so much separation. Fractures that originate near the point of impact and act to help dissipate force across the bone

Appearance and Union of Secondary Ossification centers (epiphyses): the late fusers

o Basilar suture of the skull: generally fuses between 20-22 years o Iliac crest: The thin strip of bone atop of hip fuses by early 20s. o Medial clavicle: end of collar bone in middle generally fuses sometimes in 20s but complete union can be as late as 30 years of age. o Sacrum: 1st and 2nd sacral vertebrae can fuse as late as age 30 and sometimes a little bit beyond that.

Four ways to describe the pubic symphyses

o Billowing o Ridging o Ossific nodules: big bumps of bone o Texture: smooth, porous et.

4 parts of pubic symphysis

o Ventral border: o Dorsal border o Superior extremity o Inferior extremity

Displacement

occurs when surfaces that were previously continuous no longer meet or meet at an unnatural angle. Two types: complete fracture or infraction (incomplete fracture)

Ventral arc

tends to be present in females but not in males. Slightly elevated ridge of bone that sweeps inferiorly and laterally across the ventral surface of the pubis.

Using the pelvis for sex determination

• 95% of the time having an intact pelvis a forensic anthropologist will be able to accurately determine sex. • Pelvis is very fragile and often won't be available.

Postcranial skeleton and determining ancestry

• A few traits have been suggested for differentiation ancestry • Straightness/Bowing of shaft of the femur. Anterior bowing if present. People of European and Asian Ancestry tend to have bowing of the femur. While people of African Ancestry have much more straight femurs. • Torsion of the femoral neck. Take femur and lie it done on the table with anterior side up and see how much the neck and head of femur are turned relative to rest of femur. European and African ancestry have relatively less torsion and asians have pronounced torsion.

Accuracy and problems with Giles and Elliots formulae

• Accuracy: 83-88% of skulls in their database correctly classified • Problems: used American Indian sample from a single prehistoric site (Indian Knoll) Problem because it was old and only from one site. People are always changing so it was outdated and not statistically representative. • Formulae need all 8 measurements. Broken or fragmentary skulls can't be assessed.

3 Major Ancestry Groups in the U.S.

• African-American (sub-Saharan Afica) • Asian-American (includes Native Americans) • European Ancestry (Includes Middle East and India) • General broad convenient groups

Accuracy of age determination depends on

• Age category you are working with. Estimation for subadults are generally more accurate than those for adults. Because children are going through a wide range of change. • Skeletal elements you have available. • Aging method that you use.

Cranial suture closure and age determination

• Age estimation for adults less precise than for children. • Variety of techniques microscopic, anthroposcopic, radiologic to determine adult age. • Oldest adult aging techniques. Sutures are gradually obliterated over lifetime. Always begins endocranially (inside of skull). • General correlation with age, but there's a lot of variability giving a very rough age estimate. • Meindl and Lovejoy ectocranial system: Score 10 different specific points on the skull on a 0-3 scale. Add up score from 10 spots and refer to table for rough age. Precision: standard deviation is 8 to 12 years.

Discontinuity

• Any break in bone • Two different categories: displacement and fracture line

Problems with using pubic symphyses for age determination

• As revealed by the age distribution of Suchey-Brooks phases • Tight distribution in early phases, all over the place in later phases.

Causes of trauma

• Bludgeons • Projectiles • Cutting and chopping instruments • Any hard surface • Large Moving objects • Static or dynamic pressure • Heat and chemicals • Fractured bone is not necessarily a sign of trauma. Pathological fractures occur in bones that have been weakened by disease.

Properties of bone

• Bone's composite composition (collagen and calcium phosphate) give it resistance to both compression and bending. On one hand bone very strong. • Living bone is flexible and will bend in response to force. So on the other hand flexible. • But it will break if stressed beyond its ability to withstand force.

Nose: Bridge

• Bridge: the ridge of bone that is formed by the nasal • European have a nasal bridge that resembles an A-frame house. Have a high nasal bridge • Africans have low nasal bridge sometimes described as having a quanset hut shape • Asians have a low nasal bridge but has the shape of a sagging tent.

Dental traits and determining ancestry

• Carabelli's cusps; an accessory cusps on the maxillary first molar on mesial lingual part of tooth. Most common in people of European ancestry and not other groups. • Shovel-shaped incisors in Asians. Shape of upper front teeth are spatulate in European and African ancestry. • Especially here don't forget that certain traits are found in other traits. So this could be found in people of Asian and African ancestry.

Face: Cheekbones

• Cheeckbones (shape of the zygomatic arch) • Look at bottom of the skull • Can be forward-projecting (Asian) or swept-backwards (European and African)

Standards for age determination

• Clinical studies of living individuals. E.g. childhood growth • Known age skeletal collections. Terry, Hammon-Todd, ARF collections. However, very few infants or children in them.

When looking at child development we look at

• Dental development • Appearance and development of epiphyses • Long bone formation

Face: eye orbits

• Eye orbits • Europeans: Angular eye orbits, Tilted downwards • Africans: Rectangular eye orbits. • Asians: Round eye orbits

Using dental development and eruption for age determination

• Four developmental processes scored • Good method to use because dental development is under strong genetic control and do not depend so much on environment. • Go to method of aging • Look at a couple development charts. One shows tooth formation another chart shows general stages of tooth development from in utero to 35 years. • Makes estimate more accurate.

Anthropometric methods of sex determination

• General bone size is not that great but becomes more accurate when you know ancestry. • Univariate, bivariate, and multivariate metric methods. Single measurements and indices not that useful. So use multivariate methods that do just as well or better as anthroposcopic methods. Usually use in combo with anthroposcopic methods. • FORDISC is the method of choice. Contains reference data of skeletons of well known age, sex, and ancestry. Can use as many measurements as you have available to you. Results will tell you which sex and ancestral group you skeleton best fits into and how confident the program is that your skeleton fits this profile.

Procedure for estimating stature

• Generally measure maximum length of a long bone and plug that into a formula and get a stature estimate. • Relatively simple. • In very old adults you need to correct for age disc between vertebrae shrink and they will be shorter. Always error ranges built into these. • Tend to use major long bones some studies use long bones in hands in feet but they are not as accurate.

Attempts to improve Giles and Elliot's formulae

• George Gill and Miles Gilbert (1990) • 3 nasal indices to measure projection of nasal region • Accuracy: Around 80%, methodology more sound • Problem: special measurement tool (simometer) required

The concept of race

• Great chain of being. Ancient idea. • Physical differences become markers or symbols of status differences. Looking a different way automatically puts you in a different rank. • Biological races do not exist but there are physical differences between groups of different people

University of Tennessee Forensic Databank FORDISC

• Have lots of modern skeletons • Have a good sample that's always grown and only improved • In 1993 FORDISC was created. Good because it's not too expensive and can be run on any PC and will permit you to run your statistics on whatever measurements that you have available. The more measurements you have however you have more accuracy. Can classify sex and ancestry at same time and gives you graphs and numerical results. • People still use this today • Not always right. If it has an unknown skull it will force it into a group (it wil tell you this though)

Metric analysis of determining ancestry

• Indices and direct measurements haven't really worked out very well. But a few indices have had a little success. • Giles and Elliot (1962) • First attempt to use cranial measurements and multivariate statistics to distinguish skulls of European-Americans, African -Americans and Native Americans • Based on 8 Measurements of skull • Looked at skulls from Terry Collection for Africans and Europeans. Used pre-historic Native Americans from the site Knoll.

Questions to ask for trauma analysis

• Is there evidence of trauma? • Is it related to the cause of death?

sternal ends of ribs and age determination

• Iscan and Loth developed methods in mid 80s. Used rib number 4 as standard. • Can generally be used on all of the ribs. • Patterns of changes: Adolescents tend to have wavy billowy pattern. In early 20s that surface turns into a V-shaped pit. By late 20s pit widens and has a U shape. In 30s U-shaped pit will become wider and border and rim will start to become irregular. In 40s and 50s the rim becomes even more irregular and sometimes gets jagged and sharp ridges and bone becomes brittle.

Why is ancestry important in forensic anthropology?

• Knowing ancestry can help narrow down the search for missing persons • Stature estimation formulas are ancestry-specific. Body proportions differ slightly between people of different ancestry. • Sex determination by general bone size is most accurate if ancestry is known.

Nose: Lower border

• Lower border (nasal sill) • European ancestry the lower border of the nose is very pronounce and forms what is called a nasal sill • In people of African ancestry there is no sill but often has "guttering" and have just a smooth slope • Asian ancestry the lower border of the nasal opening is flat and sharp but not a big sill seen in Europeans

2 principle methods of sex determination

• Macroscopic (anthroposcopic) • Metric (osteometric)

Long bone length and age estimation

• Measure bones without epipheses which tend to be lost because they don't yet exist or aren't fused. • Not as precise as dental aging • More individual differences than teeth • Sex differences • More affected by things like illness and malnutrition compared to teeth. • Has increased error range as you go up in age. Only useful for fetal and infant material.

Appearance and Union of Secondary Ossification centers (epiphyses)

• Most useful between ages of 10 and 20 years. • Usually scored in a 3 or 4 point scale 0: no epiphysis 1: Ununited epiphysis 2: Partial union 3: Complete union • General observations on epiphyseal union: several years laps between partial and complete union. Sex differences in timing. Females in general are 1-2 years ahead of males. Method complicated by individual variation which is high.

Sex determination: anthroposcopic methods

• Most useful for sex determination is for the pubis because it is most affected by child birth.

Trotter Stature Formulae (1970)

• One of the most commonly used formula • Not every ancestry well represented • Tibia has been excluded because they had errors in measuring tibia.

Age determination in young children and infants using union of primary ossification centers

• Only use with very young children. • Skull: Metopic suture which divides frontal bone in two in infant and is generally fused around two years of age. Right and left sides of mandible also fuse around two years of age • Occipital bone: Starts off as four different pieces, which fuse by 5 to 6 years of age. • Vertebrae: Body and right and left pieces that for the neural arch. Left and right pieces fuse at 2-3 years and arches fuse to body around 7 years of age.

Nose: Openings

• Openings (shape and width of nasal aperture) • Narrow and has shape of isosceles triangle in Europeans • African Ancestry the aperture tends to be wider and equilateral triangle. • Asians have an intermediate shape

osteoarthritis, tendon and ligaments attachment and age determination

• Osteoarthritis • Ossification of tendon and ligament attachments: Sometimes soft tissue turns into bone as you age. Sometimes get polishing of joint surfaces where bone starts to rub directly on bone. Margins of joint surfaces tend to get liping. Get little bits of bone growth in random places. • In vertebral column you see lipping that occurs after age 40. • Ossified cartilage: Thyroid cartilages and costal cartilages.

Morphology of the jaw and determining ancestry

• Palate shape • Look at underside of skull • European ancestry have parabolic, almost V-shaped, palate. Often leads to dental crowding. • Africans have broad, U-shaped, almost rectangular • Asians have a rounded palate, elliptical

auricular surface of ilium and age determination

• Part of hip • Part where ilium meets with sacrum is called the auricular surface. • Developed in 1985 by Lovejoy and colleagues. Claimed you could do good age estimates after age of 50. • Also feature deep within the pelvic structure and is usually well preserved even after burning. • Look at billowing, striations, granularity, density, porosities (small and large), retroauricular activity (as you age the retroauricular surface becomes more rough and irregular)

Bone remodeling and age

• Procedure: count number of osteons and osteon fragments, % of lamellar bone remaining, then plug into a regression equation to predict age. • Curley 1965: took thin sections of shaft of femur and examined them under microscope. Ubelaker and him made modification in 1978 • Can be done on bone fragments, gives accurate age estimates into 60s. Disadvantages: destructive techniques, time consuming, requires specialized equipment and money. Rates of bone turnover rates change with age. Hormone differences and things like osteoporosis can throw off age estimate. Probably not more accurate than anthroposcopic techniques.

Morphology of the face in determining ancestry

• Profile (alveolar prognathism) • Eye orbits • Cheek bones

Face: Profile (alveolar prognathism)

• Projection of lower face relative to the main plane. • Related to the size of the jaw • Good way to asses this is to imagine a line connecting the tip of the nasal bones to the forward most projecting part of the maxilla. Angle of line helps you see prognathism • European tends to be straight up and down and sometimes proceeds backwards. • Africans have line tilted forwards with jaw sticking out • Asian ancestry intermediate

Estimating living stature from the skeleton

• Reasonably accurate if using correct formula • Stature is going to vary by population and between the sexes. • Best stature formulae are specific to both ancestry and sex.

Suchey-Brooks Male and Female Standards for age determination

• Reduced Todd's 10 phases down to 6 and added an early and late patterns to the phases. • Created standards based on collection from LA medical examiner and so a little more modern than Todd's collection. Also created separate standards for males and females. Still heavily weighted between young males.

Nose: Root

• Root (nasal bone projection at the root) • Looking for the amount of projection relative to the plane of the face • Number 1 on the slides • Europeans have high root of the nose and the width of it is quite narrow • Africans and Asians have much lower nasal root projection

Can physical anthropologist determine ancestry based on physical characteristics?

• Someone could easily distinguish between 1,000 people that are native Nigerians, native Chinese and native Norwegians in an audience. • What about an audience of skeletons? A physical anthropologist with good training would be able to come close. • Skull morphology varies with geographic origin. • All classification categories break down at the boundaries. It's going to be a gradation, not discrete categories. • Pure races never existed in evolutionary history.

Nose: Spine

• Spine (anterior nasal spine) • Number 2 on slide. Little projection of the bone in the middle low part of the nose • Pronounced in people of European ancestry. Large and projects forward. • Africans have much smaller or practically non-existent spine • Asians have a small anterior nasal spine but generally larger than Africans

Cause of death

• The mechanism of death • The physiological events leading to death (total cessation of life processes) • By law, cause of death is determined by a forensic pathologist or medical examiner (not a forensic anthropologist) • Examples: myocardial infarction, stroke, exsanguination (bleeding out), electrocution, asphyxiation, drowning

Word used in anthropology to describe race

• The word race comes with a lot of baggage. • 1960s anthropologist, Ashley Montagu, suggested new term, which was ethnicity. Problem: what is the biological meaning of the ethnic group? A dictionary definition: sizable groups of people sharing a common or cultural tradition. • Physical anthropologists prefer term ancestry. Term ancestry reflects biological history. Not confounded by cultural constructs like race and ethnicity. Refers to physical, not cultural, differences. Refers to geographic origins and genetic relationships.

Aspects of trauma that are of medicolegal interest

• Timing trauma: perimortem trauma is of particular cases in forensic cases. • Force that caused the trauma. If force is a weapon then the shape and size of the weapon will be of interest. • Number of wounds. If you have an individual with multiple gunshot wounds then it is unlikely suicide. • If multiple wounds, the sequence of wounds. • Placement of wounds. Can inform us of manner of death, location of attacker, potentially the height and handedness of the attacker.

Reporting Age and Sex Estimates in Forensic Reports

• Use phrases like "consistent with" that don't imply that this is 100% the correct answer. "strongly indicate" "suggest" • Want to say look at all the methods I used and this is what it implies.

why multifactorial aging?

• Want to use all available methods for aging as possible. • Skeletons are often incomplete and so you can't rely on one particular method because you might not have that feature available. Want to have a lot of tools available. • Allows you to avoid the trap of an anomalous feature. Individuals might have an outlying feature.

Cause of death vs manner of death

• What is the difference between the two, and why is it important? • Trauma looks at both cause of death and manner of death