Forensic Anthropology Exam 3 Review

Statistical method

measuring the length of a bone and using variables such as age, sex, and gender to determine the stature

What modern populations are reported to have the highest average stature?

the Dutch are tallest: the average height in the Netherlands is 6ft 1in -Netherlands, Sweden, Denmark, Norway, Estonia, Finland, Germany, Greece, USA, Australia

manner of death

the circumstances that led to a persons death

Anatomical method

*if you have all the bones contributing to height* laying out and measuring the exact stature of an individual. Use a correction formula to factor in missing soft tissue to get a more accurate measurement

Ring fracture

- Blunt force trauma - head first/feet first falls causing the skull to be forced onto the vertebral column - or event causing skull to be pulled away from vertebral column

What are the three major anatomical methods discussed in class?

- Dwight - Fully - Raxter et al.

If the remains are consistent with those of a child or juvenile/subadult, what are at least two methods we discuss that are applicable to cranial remains?

- Primary Ossification Centers - Dentition

Fully and Pinneau method

- Revised stature estimating eqations by including lengths of components of the vertebral column. - Uses long bones AND the torso for statue estimation - 2 predicting equations Stature = 42.67 + 2.09(fem+5 lumbars) +/- 2.35cm Stature = 48.63 + 2.32(tib+5 lumbars) +/- 2.54cm - Data composed of 164 male skeletons from WWII, may not be a god fit for todays population of for European Americans

Estimate age at death for fetuses and neonates

- Standardized age-related crown-rump lengths and stature are typically used. - For skeletal remains, the relationship between age and long bone length is linear, allowing bone length to be used to estimate age at death for fetal remains up to the birth.

Elastic or Youngs modulus

- Stiffness - When the stress is shear, it is called the shear moulus

Trotter and Gleser method

- Use all long bones for stature estimation (humerus, radius, ulna, and fibula) - Introduced a correction factor for older individuals (height decreases by about .06cm per year after age 30. To correct, subtract (0.06cm x age-30) from your height estimate) - Expanded their racial sample to include Asian war dead

Ossific nodules

- blobs of bone on the pubic face that can be seen in early adulthood - appear with increasing age

For the exam, BE ABLE TO CALCULATE STATURE FROM FEMUR USING FORMULA. What if you have a femal femur but the only thing you have is a male formula? How do you calculate the females stature?

- convert feet and inches to just inches (i.e. 5'2'' = 62 inches) - multiply by the correction factor of .92 - convert back to feet and inches

Histology of teeth

- employed to estimate age at death in adult skeletal remains - changes in the dentine and cementum - Dental Root Transparency (Bang & Ram)

Sex and age at death are factors when determining stature. What are the limitations these factors place on stature estimation and how might these be addressed?

- formulas vary based upon the sex and age of a skeleton (difference between male & female stature or stature of and old person vs. stature of a young person) - need specific bones to determine age and sex (mainly skull and pelvis) - using statistical method is quantitative but sex and age are qualitative. Someone could perceive a male pelvis as female, therefor using a different formula for stature estimation on the same bone - try creating formulas that dont rely on observable characteristics?

What are 4 major bones that histological age estimation methods are available?

- human rib - long bones: femur, tibia, and fibula - the midshaft rib and clavicle (Stout & Paine)?

What is the conversion from to metrics? 1 in = ? cm 1 in = ? mm

1 in = 2.54 cm 1 in = 25.4

What is an important distinction between how stature is determined in Dwights original method and its modification by Fully?

1. Bone measurements are put together, rather than articulating the bones themselves 2. A single correction factor used to account for all spaces (soft tissue correction)

5 things to remember when using the Trotter and Gleser method

1. Choose the formula on the basis of smallest error to determine stature. Do not average several equations 2. It does not matter whether the left sides are used 3. "The tibia issue" - when using this methods 1952 version, you must use the 'ordinary length' of the tibia which measures the tibia without the malleolus. For the Trotter and Gleser 1958 formulas using the tibia method that does include the malleolus 4. Secular changes since the formula was developed: Jantz tested this for females and found that both blacks and whites have experienced secular changes in bone length. Whites have experienced a change in proportion as well. Adjusted formulas available only for African and European ancestry males and females 5. For cases where no female formula is available, Asian and Hispanic females, the result for the male formulas appropriate for these ethnic groups can be multiplied by 0.92 (6.) Use of the Wilson et al. new formulas do not include a general formula that can be used if ancestry is unknown

What are the 6 basic goals of skeletal trauma analysis?

1. Distinguish pathological conditions for normal variation 2. Determine time trauma occurred: Distinguish ante-, peri-, and postmortem injuries 3. Determine force, size, construction, and shape characteristics of trauma 4. Determine nature of object causing trauma: kind of weapon 5. Determine number and sequence of skeletal injuries 6. Describe location of wounds

Things to consider for age estimate form dentition

1. Females mature quicker in their dental development. For females their estimated age should be reduced by 3-6 months 2. Age range increases substantially after the age of four. By twelve the age range has doubled and by sixteen the age range has tripled

Stages of epiphyseal union

1. No union 2. Unfused 3. Fused 4. Obliterated

What are the 3 most often relied upon gross morphological (i.e., non-microscopic) methods used by forensic anthropologists to estimate age-at-death based upon the os coxae.

1. Transverse organization - Billows - Striations - no transverse organization 2. Surface bone - coarse grained - fine grained 3. Porosity - small vs. large

Problems with using tooth calcification information

1. dental formation is generally only visible in x-ray 2. information on deciduous dentition available for mandibular canines and molars 3. Dentition schedules for deciduous teeth are divided by sex 4. Dentition schedule for permanent teeth are divided by sex and ancestral group 5. Workers often disagree as to the amount of development visible in x-rays

Dentition and Age

Adult: 28-32 teeth Deciduous: 20 teeth

Advantages and limitations of anatomical methods compared to statistical methods?

Anatomical methods can be more accurate for specific individuals but they are more time consuming, in need of more parts of the skeleton, and requires anatomical expertise. You also need standards for accounting tissue thickness when calculating the stature using anatomical method

Age and Primary Ossification Centers in Infant Skulls

Appearance of actual growth centers themselves is usually not applicable in forensic anthropological analysis. Why, and how are they used? Status of Fontanelles. Seen by the presence or absence of gaps (Fontanelles) between the centers. The joining of these primary centers are more likely to be recovered which is why it is more useful for forensic anthropology Another way of putting it, The fontanelles are the gaps that close and turn into cranial sutures. You are examining which cranial sutures are still open and which ones have begun to close.

Obliterated

As people age, the process of bone remodeling completely obliterates the separation line

Wilson et al. method

Based on a new data set, uses new modern data Only enough data to provide new formulas for whites and blacks of both sexes. Still use Trotter and Gleser for Asians and Mexicans

What is the term used in class and in your text for the change in the average stature observed over time for populations, and could it require developing new statistical methods?

Bergmanns Rule- there is a negative correlation that exists between body weight and mean annual temperature (high body weight in low temperatures and low body weight in high temperatures) Over time, formulas must change when populations begin to get taller or body proportions change

What compromise does bone make with regards to stiffness and compliance?

Bone has to be stiff enough to be a good lever but compliant enough to not break

Sharp force trauma

Cause by implement with an edge or point

Posterior Fontanelles

Close several months after birth

Lateral Fontanelles

Close soon after birth

Compound fracture

Complete fractures in which bone protrudes through the skin

Failure point

Continued loading beyond the yield point can reach the failure point resulting in fracture

What are the 5 major force characteristics used to describe trauma?

Direction Speed Focus Blunt force Sharp force

When a significant force is applied to a bone, it can produce a break called a discontinuity. What are the three types of discontinuity as we defined them?

Displacement Complete fracture Infraction

Subadults

Divided into stages. During this period, age estimate at death is more accurate and precise. Changes from growth and development can be utilized.

What is an important method we discussed that based upon age based changes in aspects of postcranial skeletal remains?

Epiphyseal Union - most useful to estimate age at death between 10 and 25 years

Immature skeletons

Everything discussed has been for measuring adult stature because there we lack available large series of sub adult skeletal remains for which living stature is known

What does it mean that stature values for populations/samples are normally distributed, and why is this significant for stature analysis?

It means that the distribution of frequency of heights has the same mean, median, and mode. This is important in using statistical analysis

Infancy

Period which the mother provides all or some of the nourishment to the offspring via nursing. It ends with weaning, which in pre-industrialized societies occurs at a median age of 36 months.

What are the 5 Manners of death as defined in forensic analyses?

Homicide Suicide Accidental Natural Unknown

Age at death

Important part of developing a biological profile. Method of choice depends on whether the remains are those of a sub-adult or adult.

Hinge fracture

Infraction that is still attached to its original bone, the surfaces meet at an unnatural angle

Age estimation for adult skeletal remains

Initially based upon morphological changes relating to the effects usage, wear and tear, and degenerative changes to bones, especially at joint surfaces Evidence of arthritis especially at joints and vertebrate are used to indicate advanced age, but this is also affected by factors other than age (level and kind of physical activity an genetics)

Biomechanics of the bone

Knowing the biomechanics of the bone will help determine trauma

Facial trauma

LeFort fractures

Anterior Fontanelles

May remain open for three years, but usually closes by 17 months and is closed in most individuals by 31 months postnatal

Compression fracture

Most common in skull, can be observed in any bone as inward displaced cortical bone and can be either complete or incomplete

Subadult Stages

Prenatal and fetal Infancy Childhood Juvenile Adolescence Adult

What is the difference between Fullys method and the modification by Raxter et al.?

Raxter provided a modified version of the stature formula that show increases in the accuracy. - Fully developed the method using white males from France. Raxter has show that the factors are applicable to blacks

Sternal ends of ribs and on the auricular surface of the ilium

Similar to symhyseal, these areas are composed originally of smooth and youthful-looking bone that eventually becomes old and pitted with osteophytic development

Standards for bone lengths and age

Standards are population specific. - growth rates and environmental factors differ between populations. They may not be applicable when the individual is from a population other than the one from which the standard measurements were derived.

What are the two major methodological approaches to estimating stature for skeletal remains?

Statistical & Anatomical

What is the difference between statistical and anatomical methods for estimating stature?

Statistical method uses one long bone to determine stature while anatomical requires you to have all parts of the skeleton contributing to height

Why is body (skeletal) proportion important for evaluating statistical stature methods?

Statistical methods are based upon the correlation between bone length measurements and stature

What are 2 different kinds of methods that can be used to estimate age for incomplete fully adult skeletal remains, i.e.,consisting of merely a torso, i.e., no skull, arms, or pelvis.

Sternal rid ends clavicle

Diaphyseal lengths for femur, tibia, and fibula

Used to assess the more general question of before or after birth.

Vertebral epiphysees: epiphyseal ring

Useful in narrowing estimated age at death ranges from teenage and young adult skeletal remains. [Note that females show an earlier initial union activity (12 years for cervical vertebral ring and 14 for thoracic), compared to 16 years for males for both cervical and thoracic vertebrae.]

Important mechanical characteristics of bone when loaded expressed by a load and deformation (stress and strain)

Yield or Failure Point The area under the curve Elastic or Young's Modulus

Postmortem

after death: dry bone response

Fused

as time goes on, growth ceases, the epiphyseal caps unite to their diaphyses leaving a temporarily line where the two structures were once seperate

Butterfly fracture

associated with compression during bending. Significant force causing a triangle of bone to break away forming a comminuted fracture

Perimortem

at or around time of death: no healing

Prenatal and fetal

before birth

Antemortem

before death: healing

Adolescence

begins with puberty, and ends with early adulthood. Secondary sexual characteristics are developing and rapid acceleration in growth of all skeletal tissues occurs, and ends with earl adulthood.

Manner of death vs. cause of death

blood loss

Avulsion fracture

break produced by muscle pulling a portion of the bone away from attachment site

Comminuted fracture

breaks that result in the production of multiple fragments of bone, common in death by violence (bludgeoned of the skull)

Symphyseal surface

changes from an area covered with ridges made of fine-grained bone to a flat area with porous, rough, and otherwise "old-looking" bone

Palatal sutures (roof of the mouth)

complete obliteration of these sutures show signs of advanced age

Adult

defined by the completion of growth and full reproductive maturity.

Colles' fracture

due to fall on outstretched hand causing dorsal displacement of distal radius fragment

No Union

ends of bones are covered by cartilage that will eventually ossify

Unfused

epiphyses ossify within the cartilaginous joint area, conforming closely to the join area

Cause of death

factors that led to somatic death

Parry fracture

fracture due to bending - defensive wound

Green stick fracture

infractions- breaks in the bones where seperation between the broken ends does not occur

What does it mean that bone is "anisotropic"?

its material properties differ depending upon the direction

Exit wound

larger than entrance wound and beveled outward

Cranial sutures

lines separating the bones of the skull (including the palate) close with age until they fuse and may eventually obliterate - The degree to which the sutures of the cranium have closed and become obliterated has been used to make rough estimates of age at death for a long time.

Juvenile

pre-pubertal individuals who are no longer dependent upon their parents for survival

What postcranial element (bone) can be examined to determine if the remains are broadly speaking those of a young or older adult?

pubic symphysis auricular surface of the ilium sternal end of the rib

Entrance wound

smaller that exit wound and beveled inwar

What do "stress" and "strain" refer to with regards to bone biomechanics?

stress- forces per unit area. material level force strain- relative deformation expressed in terms of parts per million

How is it possible to determine the sequence for multiple traumatic defects?

the fracture lines will be running into each other in chronological order

Childhood

the period of following weaning, when the child still depends upon older people for feeding and protection, and cannot survive without this care

What microscopic feature is used to estimate age histologically?

the presence of osteons in the bone

The area under the curve

toughness. the work or energy required to fracture

LeFort fracture

unique fracture patterns that can be observed for facial trauma 1. Blow to the lower face from the front side 2. anterior blow to the midface 3. centrally located blow to upper part of the face

Spiral fracture

usually caused by sudden, violent, rotating movements, such as twisting the leg during a fall