Week 4 notes (EXAM 2 MATERIAL)
Week 4 notes (EXAM 2 MATERIAL) ANT3520
Popular in Skeleton Keys: Introduction to Forensic Anthropology
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AP Environmental Science
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This 14 page Class Notes was uploaded by Janaki Padmakumar on Friday July 22, 2016. The Class Notes belongs to ANT3520 at University of Florida taught by Amanda Friend in Summer 2016. Since its upload, it has received 6 views.
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Date Created: 07/22/16
Week 4 Notes L13 Race Ancestry and race are differentiated terms Race: It is a social reality but is not a valid biological entity Varied continuous spectrum- no distinct or discrete groups Not universally defined groups Social race and biological ancestry Social race or ethnicity- is peer and self defined; in group, constantly negotiated terminology Defined by physical appearance and genetic heritage, geographic origin, cultural practices and linguistics Biological ancestry- metric and nonmetric skeletal traits distributed along a broad scope of geographic and population groups Early racial ideologies Humans can be categorized in discrete groups Groups are static- biological determinism (you are this because that’s what you are; applied to ideas like criminality, job determination etc.) Race determined based on phenotype, behavior and moral character Current ideas on race: Gradient in human variation Variations are found within groups rather than between different groups Examine ancestry, not race Clinal variation- broadly distributed species will vary in genotypic and phenotypic characteristics gradually over their range Variety caused by environmental differences Patterns can be driven by selection or can be an artifact of genetic drift, and are modified by gene flow Why determine race? FA is applied field of anthropology Interact with laypeople and provide information within a social context so that others can interpret it Provision of a service Establish identities and narrow the scope of antemortem searches Sauer- translating info about bio. Traits to a culturally constructed labeling system likely to be applied to a missing person Ancestry= broad, geographically defined biological populations Categories used reflect everyday use in our society L14 Ancestry Ancestry- broad, geographically defined biological groups Three primary ancestry groups in the US Asian (Native Americans included) European African Ancestry determination Non metric- morphological variations Metric Skulls (cranium and mandible) Sometimes postcranial elements- used sparingly Non metric determinations Visually determined Not easy to measure Normal variations in the skeleton Not related to pathology or trauma Non metric traits need to be: Documented for large samples (need to capture large variation ranges) Clearly illustrated and defined without any ambiguity Quantified Non metric scoring 1 Present/absent- either complete or incomplete 2 Quasicontinuous- small, medium, large Traits: Interorbital breadth Orbit shape Nasal aperture Nasal bone shape/form Midface prognathism Zygomatics Dentition Sutures formation Mandible Overall skull form Inerorbital breadth Broad, intermediate or narrow (compared to overall face shape) Nasal aperature width- wide, medium or narrow Inferior nasal aperature- scoring: Guttering Incipient guttering Straight nasal sill Partial nasal sill Complete nasal sill Nasal shape Round (quonset hut) Oval Plateau (tented) Vaulted Triangular (steepled) Post bregmatic depression Small concavity on the saggital suture just past bregma Zygomaticomaxillary suture: Angled - European Smooth- Asian S shaped- African Americans Obliterated (can't be seen); Asian Palate shape Round; Asian Parabolic; European Rectangular ; African Midface Alveolar prognathism in African pops; lower jaw area projection Flaring zygomatics in Asians Receding zygomatics in Europeans-lateral orientation Non metrics associated with African ancestry Quonset hut nasals Guttered nasal areas with no nasal sill Post bregmatic depression Simple suture pattern Slanted ascending ramus Rectangular palate Alveolar prognathism Vertical zygmoatics Multiple mental foramen Wide nasal aperature Rectangular orbits Broad interorbital breadth Long headed Anterior facial prognathism Small nasal spine European ancestry Sloping orbits Tower or church steeple nasals Often have trace of metopic suture Depressed nasion Large nasal spine Sharp nasal sill Simple suture pattern Pinched ascending ramus Parabolic palate Retreating zygomatics Prominent chin European: o Includes all population of European descent o Narrow nasal aperature o Narrow interorbital breadth o Steepled nasal bones o Long headed o No facial prognathism o Large nasal spine Asian ancestry Rounded orbits Tented nasals Malar tubercle Indistinct nasal sill Complex suture pattern (bones within suture) Wide, vertical ascending ramus Straight palatine suture Round palate Shoveled incisors Buccal pits Wormian bones Projecting/flaring zygomatics Comparatively flat face Medium width nasal aperature Rounded orbits Tented nasal bones Brachycephalic- round headed Little facial prognathism Moderate nasal spine Shovel shaped incisors Preponderance of traits (Hefner 2003) European- 46/130- 35% Asian- 107/211 - 51% African- 20/117- 17% *No skeletal markers to correspond perfectly to geographic origin* Non metric analysis disadvantages Inter-observer error Assessment is subjective Not clearly defined o Possibility for intra-observer error Rudimentary statistics o Simple trait frequencies Metric analysis Standard measurements validated with statistics 1962 Giles and Eliot- cranial measurements to assess ancestry UT- forensic databank Metric analysis and FORDISC Remains measured then entered to FORDSIC Compares likelihood of skeleton being part of a certain ancestry group Use comparison to other reference samples to determine ancestry Nature of variation Spectrum of traits Overlapping traits More variation within groups L 15 Stature Stature- standing height Bodily proportions consistent from person to person usually Predictable relationship between limb length and stature Genetic and environmental factors affect stature Trauma and pathology can leave effects on height- acquired and congenital Age, sex and ancestry can cause variance Age: Stature increases to adulthood, then decreases with age o Not a standardized rate of decrease o Vertebral compression and bone diseases results in height loss (loss of vertebral disc space) Sex: Sexual dimorphism- males usually taller than females Differently proportioned limbs Must determine sex before stature for accuracy Geography: Human body form consistent with ecological rules by Bergmann and Allen- clinal distribution Related to ancestry Bergmann and Allen: o Rules to maintain homeostasis- size correlates to heat regulation; hot climates need more surface area to disperse heat o Allen: hot climates have longer appendages, cold climates have shorter appendages o Bergmann: hot climates=smaller body volume (lean build), cold climates= more volume (stockier build) Methods to determine stature: Based on measuring all skeletal elements, and some selected skeletal elements Fully 1956: o All skeletal elements that contribute to stature o Added in a soft tissue correction factor o Developed a series of height equations o Issues: Small sample size; n=102 All white males used (inaccuracy for females and other ancestry groups) Samples died in WW2 concentration camps- health issues Requires a nearly complete skeleton o Linear regression: Measure a long bone and then apply linear regression formula (has error margins to accommodate for height variance) Need to know ancestry and sex Based on Trotter and Glesser's work Started work at JPAC- remains from WW2, Korean war and Terry skeletal collection; had male and female remains Strongest correlations between long bones and height Formula example: Male, European, tibia 355mm Stature= (2.52(355)+786.2)/25.4= 66.17 inches (point estimate) Range= point estimate+/- 1.33 inches o FORDISC 3.1 Living v Forensic stature variations Self reporting : o Self reporting like in licenses o Usually inaccurate o Overestimated, usually by males Age: o Increased age-> decreased stature o Vertebral body compression o Correct by subtracting from estimated stature based on age Time of day (effect of gravity over the course of the day) Measurement errors Secular change Cadaver stature (vary up to 2 inches due to decomposition changes) Stature/Age accuracy Long bone length is an accurate way to estimate age up until 12 years o Conserved relationship between age and stature in kids Used for prenatal (fetal), natal and postnatal remains Accuracy- 0 months- birth: very accurate; fetal growth is highly constrained with narrow tolerances for survival o Cannot be allowed to grow unrestrained o Haase's rule o Length can be used to calculate fetal age Birth- 2 years: fairly accurate o Catch up growth to compensate for fetal deficiency o Weaning time and duration differences 2-12 years more accurate o Fairly consistent growth trajectories o *not a lot of mass factored in* Teenagers- less accurate o Differences in timing and degree of growth spurts (sexual dimorphism) Adults- very accurate o Fixed stature since bones are done fusing, until later degeneration L16 Personal ID Importance of individual identification Closure and emotional peace for family members Official documentation o Probates, inheritances o Insurance o Contracts o Other social institutions (social security, medicare, etc) Corpus delicti o Body provides evidence of a crime being committed o Prosecution of offenders Medicolegal identification- civil matter tendered in the form of an expert opinion and based on preponderance of evidence (weight of evidence varies by case) Positive evidence: Goal of every forensic case Most rigorous scientific standard Absolute biological proof of ID Easier with a single decedent Example- nuclear DNA matches with known exemplar; fingerprints; antemortem/postmortem radiographic comparison, surgical devices with serial numbers Biological profile CANNOT positively identify an individual Presumptive evidence- reasonable conclusion based on logic Not definitively exclusive; can match more than 1 person, and assumptions can be false E.g- mitochondrial DNA match Group characteristics Concordance between antemortem fracture and documented medical history Wallet, tattoo, scars or moles Context- probative value of evidence based on the context of discovery; causes variations in the weight of evidence Closed v. open event Closed: know all the people involved; bodies contained; each ID yields subsequent ID (airplane crash) Open: don’t know all involved (hurricane) Personal ID- cultural factors Group affiliation Religious denomination Socioeconomic status Biological identification Demographic characteristics- sex, age, stature and ancestry Idiosyncratic biochemistry and morphology Unique life history- broken bones, surgical implants, dental work Idiosyncratic biochemistry: Sometimes can extract from bone Doesn’t work well for fossilized, cremated or inorganic bone Robust cortical bone works best Teeth not as good for DNA Can work for sex and ancestry Idiosyncratic morphology: Structures that vary in size and morphology o Clavicle o Rib 12 morphology o Frontal sinuses- extreme variations Found in 95% of population Stable pattern in adulthood, unique to each individual Radiographic comparisons o Mandibular tori o Sternal foramen o Extra or transitional vertebra o Supernumerated teeth and extra digits Skeletal anomalies Missing/extra skeletal elements Accessory foramens Unique life history markers Broken bones Pathology- joseph merrick elephant man Dental work Surgical devices or implants o 1993 safe medical devices act required practitioners to record lot and serial number of devices in surgical record of each patietn o Vendor, lot and serial number can be used for ID o Help with time of death o Artificial devices- breast implants L17 Forensic art FA not always artists apply art to medicolegal contexts Used ot create leads but is not positive ID; presumptive evidence Difficult and time consuming; art and science Forensic artists- artistically talented, but also have a knowledge of anatomy, underlying skull architecture and how it relates to soft tissue formation Biological profile information Superimposition Overlay skull image and antemortem image Osteometric points and landmarks used to align Use 2D photographs and unknown skeletal remains (need them to scale) Video superimposition Camera and electronic video mixing board, and unknown remains Computers and digital imaging equipment with unknown remains 2D forensic art ID living suspects, age of missing persons Usually based on witness recollections Facial feature depiction Freehand or with a computer Facial reconstruction (approximations) 2D or 3D- intend to identify skeletal remains Artistic reproduction of soft tissue features when no soft tissue is present Based on biological profile Freehand or with a computer 3D facial approximation Reliant on known or estimated parameters Average tissue thicknesses Anatomical knowledge of muscle and gland thickness/conformation Anatomical relationships between facial features Tissue depth Cadaver studies done- needle depth and postmortem tissue (can be dry, lacking thickness, etc) Ultrasound living individuals; CTs and MRI scans (preferred method) Techniques Start with skull or cast Apply tissue depth markers o Standard system based on normative data Roll out clay to the depth of the tissue marker; apply clay and contour voids Anatomical methods: o Not based on normative data, sculpt muscles, glands and cartilage o Not usually used Circumstantial evidence o Adornments Personal characteristics o Eye color, weight, hairstyle or color Problems: Used as a last resort methods Biological profile doesn’t match up with missing persons list Not a positive ID Efficiency depends on artist; very subjective process Not a lot of standardization Artists skills vary Tissue depth variation Potential error in measurement data Secular changes L18 Skeletal pathology Derived from paleopathology- studying skeletal remains from past cultures Normal- tissue or organ functionally intact, free from disorder, capable of sustaining its function Anomaly- deviates from norm, but is non lethal and does not significantly change function Pathological- deviation from norm in a way that compromises tissue or organ Skeletal evidence of disease Not very common; only few diseases affect the skeleton Reactions to disease are generalized and vary from person to person When disease does affect the skeleton, doesn't produce same effect all the time- requires DDX Entails abnormal bone o Formation o Destruction o Density o Shape o Size Lytic lesion o Abnormal cell destruction (circular areas that lack density) Blastic/sclerotic lesion o Abnormal cell growth Periosteal reaction New bone formed in response to injury to/stimulation of periosteum that surrounds the bone Can be caused by tumors, drug reactions, infection, metabolic conditions Common on anterior tibial shaft Osteomyelitis Any bone tissue infection Bone can enlarge and form bone buttresses or sheaths(involucrum) , drainage channels for pus (cloacae) and islands of dead bone (sequestra) Infectious disease Bacterial, viral, fungal or parasitic Bone response is slow Skeletal involvement shows a fine balance between "good" and "bad" health Syphilis Vemereal treponemal infection; heart, brain and bones affected Only tertiary syphilis affects bone o Periosteal new bone on bones closest to the skin; frontal, nasal aperature, tibia, ribs and sternum o Caries sicca- lytic lesions in the skull (moth eaten appearance; diagnostic sign of syphilis) o Saber tibia (bent bone appearance since new bone grows on one side); see in congenital syphilis Tuberculosis Airborne bacterial disease Can result in o Lytic lesions that affect vertebral bodies, noticeable in the spine, but also hips or wrist sometimes o Vertebral collapse o Little to no new bone formations near lesions (but may be present on inner rib surface) Leprosy Airborne bacterial infection Can result in: o Concentric bone loss in phalanges o Rhinomaxillary syndrome- change to alveolus and inferior nasal aperature Metabolic disease Rickets- vitamin D deficiency during development; classic sign is leg bowing (vit D required for calcium and phosphate deposition) Osteoporosis: o Most common in the elderly o Decreased bone density o Bones will be light and x-rays will show reduced trabeculae on x- ray o Vertebral and hip fractures o Kyphosis (bend in the back) Paget's disease Chronic increase in bone remodeling rate, progresses from lytic to sclerotic (quickly deposited bone; weak) Thickens cortex and causes a puffed up enlargement of bone Sacrum, spine, fermora, skull and sternum are most common sites Developmental pathology Achondroplasia- dwarfism; congenital o Caused by defective endochondral ossification- bone growth starting with cartilagenous precursor (skulls form from membraneous precursors) o Proportionally large head with frontal bosssing (large foreheads), lumbar lordosis and short limbs Gigantism and acromegaly o Pituitary gland produces too much growth hormone o Gigantism- starts before epiphyseal fusion- creates normal body proportion and bone shape; end up massive o Acromegaly- initiates after fusion; results in large browridges, mandibular prognathism, proportionally large hands and feet (results in reduced life span) Cleft palate o Partial or complete union of palatine bones and hard palate o In bone- defect in hard palate that may involve the anterior margin; more common on the left side of the mouth o Varies by race, most common for those with Asian ancestry Spina bifida occulta (mildest form of spina bifida) o Incomplete fusion of lower lumbar/sacrum spinous processes o Usually no symptoms bc not in an area with the spinal cord Scoliosis o Lateral spine curvature o Results in rotation of vertebra and can create a hump in the chest due to anterior pushing of ribs to one side Tumors Primary tumors- tissues they affect are tissues they originated in o Osteomas: Benign normal bone overgrowth Common, small, not much clinical significance Can be found on any bone, frontal bone is most common o Occurs most often in children; found in areas of rapid growth o Osteochondroma- area of extra bone o Osteosarcoma Malignant bone tumor Femur, tibia and humerus Mixture of lysis and sclerosis Periosteal reaction Large mass of spiculated bone (sunburst on xray) Most common in children; metastasis is usually what results in death (60% survival rate) Usual course of treatment is amputation to try and prevent spread o Ewing's sarcoma Malignant primary bone tumor Most common in kids and adolescents (5-30) Femur, pelvis and tibia are common Cortical erosion, rapid periosteal reaction Pathological fractures are common o Multiple myeloma Red marrow plasma cell malignancy Multiple small osteolytic lesions throughout the skeleton; most noticeable on the skull Secondary tumors- metastasized tumors o Metastatic cancer (BLT with a Kosher Pickle); originates in a different body part and spreads to the bone Breast Lung Thyroid Kidney Prostate- sclerotic Lytic lesions have undercut edges without any signs of healing Degenerative disease Occur as a result of aging Arthritis o Osteoarthritis: degenerative joint disease; wear and tear over time from general aging and use Marginal osteophytes "lipping" on margins or new bone on joint surface Alterations in joint contour Pitting of joint surface Eburnation- smooth, polished areas of bone resulting from bone to bone contact o Rheumatoid arthritis: autoimmune disorder Erosion around the joint surface Hands, feet, knees and ankles Can be disfiguring; joint articulations can be changed DISH- diffuse idiopathic skeletal hyperostosis o Form of degenerative arthritis o Fusion of contiguous vertebral bodies on front and right side of the centra o Bony spurs on certain elements due to ossification of ligaments o Most common in those who are obese or have type II diabetes Dental disease Caries- cavities (carious lesion); bacteria breakdown of enamel, then dentin Periodontal disease- infection of tissues surrounding teeth Bacterial breakdown of alveolar margins