exam 2 Flashcards
who can you estimate the sex of based on remains
adult male and females
whats the most reliable element for sex estimation
pelvis followed by the skull
female pelvis details
- greater than 90 degree angle (subpubic bone)
- sacrum is tilted back more
- Illia is spread wider
- generally bigger for childbirth
- wide sciatic notches
- ventral arc
- concave subpubic concavity
- ischiopubic ramus is pinched (if cut in half)
male pelvis details
- less than 90 degree angle (subpubic bone)
- sacrum is tilted forward
- Ilia is closer together
- small sciatic notches
- convex subpubic concavity
- ischiopubic ramus would be flat/broad (if cut in half)
metric assessment of the pelvis for sex estimation
- no necessary
- are difficult to obtain
- not as accurate as morphological assessment
female skull details
- gracile
- sharp orbital border or supraorbital ridges are slight
- round chin
male skull details
- robust
- supraorbital ridges are extreme
- large canines
- square chins
- pronounced muscle attachment sites
metric analysis of the skull for sex estimation
- less accurate/necessary compared to visual examination
- requires skill in taking measurements
other bones to estimate sex
- humerus head diameter
- scapula width and height
- femur head diameter
can subadults remains be sexed
no
how can you try to estimate developmental age
- bone length
- union of primary centers of ossification
- tooth development and eruption
- epiphyseal union
how to estimate degenerative age
- pubic symphysis
- auricular surface
- sternal rib ends
- cranial suture closure
- also cortical bone remodeling or dental changes
bone length for estimating developmental age
- good till about 5 years old
- use long bones (fibula, tibia, femur…)
- these lengths can be affected by nutritional status, disease (stunted growth)
union of primary centers of ossification for estimating developmental age
- good till about 10 years old
- fontanel fusion = soft spots on babies heads, these bones fuse at pretty standard times across board
- structure fusion
tooth development and eruption for estimating developmental age
- deciduous dentition (baby teeth)
- partially form before birth
- becomes bone by 10-11
- permanent dentition
- begins forming around birth
- fully erupted at beginning of adulthood
- teeth made of hydroxyapatite
epiphyseal union for estimating developmental age
- hundreds of these in the body (where area of growth is in long bones)
- fusion times are controlled genetically
- this is useful around 10-25 years old
- the degree of fusion is used
- obliterated = can’t see fusion line anymore
what happens after puberty to your skeleton
deteriorates
microtrauma to bones
- to pubic bones and ribs
- tiny trauma caused by everyday life experiences to your bones
- costal cartilage - attaches rib bones to sternum
- pubic symphysis over time goes from beveled to smooth/flat
early pubic symphysis degenerative age estimation methods
- Todd 1920
- Relies mainly on descriptions
- 10 stages, 5 year intervals
- Didn’t work so well
- McKern and Stewart 1957
- Divides pubic symphysis into 3 areas: dorsal, ventral, and rim
- Rarely used today
- They only looked at white males though
later pubic symphysis degenerative age estimation methods
- Suchey and Brooks 1990
- Most often used today
- Cast system = Made a cast of youngest and oldest pubic symphysis of each phase groups
- divides into 6 phases of varying length
- Based on modern autopsies of a variety of people
- A morphological system
articular surface used to determine degenerative age
- Articulation point between sacrum and ilium
- Survives traumatic injury well
- 5 aspects for examination
- Very subtle area of estimating age
- Texture changes
- Retro auricular surface (behind the surface)
- Apex “point of the ear”
sternal rib ends to estimate degenerative age
- made by Iscan et al 1984/5
- right 4th rib used to develop technique, can apply to ribs 4-7
- less precise than os coxa methods
- features to look at = texture, contour, outer margin around the rib edge, rib contour
cranial suture closure for estimating degenerative age
- technique made by Meindl and Lovejoy in 1985
- ectocranial and endocranial (inside/outside)
- where bones of skull meet
- looking at the degree of closure
- less precise than os coxa method
- complete fusion doesn’t complete till 80 years old if ever
cortical bone remodeling for estimating degenerative age
- not used often
- most accurate/precise age estimation for adults
- least common because of its destructive nature for bones
- take thin section of femur at mid shaft and cut it in half
- then cut into little section and sand down to one osteon thick
- make wet mount and view on slide
- look at ratio of whole osteons (secondary) and primary osteons (first to form when growing and replaced)
dental attrition for estimating degenerative age
- last ditch method
- look at tooth wear
- is population/culture specific
- not seen as much in modern populations
dental traits to look at for estimating degenerative age
- Cementum (outer covering of tooth roots) apposition
- Count rings of cementum like rings in a tree
- Root transparency
- Root becomes more transparent with age
- Root resorption
- Roots will resorb as you get older, there is a loss of the tip of the root
- Can only give you a vague young, middle, or old grouping
whats anthroposcopy
- Observing visually discernible differences between groups
- This can only be done on adults
- Children haven’t developed their facial skeletal structure yet
cranial traits to observe for ancestry estimation
- Only use the cranium for ancestral estimation
- Nose
- Face
- Vault
- Jaws and teeth
observing the root of the nose
- where the nasal bones meet the frontals
White - high and narrow
black - low ridged, broad
Native american/Asian traits fall in between
observing the bridge of the nose
- ridge of bone formed by the nasals
White - high and arched
Black - low and sloped
Native american/Asian traits fall in between
observing the spine of the nose
- projection at the inferior nasal border
White - very pronounced
Black - almost non existent or very tiny
Native american/Asian traits fall in between
observing the lower border of the nose
- the nasal sill
White - very sharp sill, almost a projection
Black - have more of a “gutter”, looks scooped out
Native american/Asian = sharp but not protruding
observing shape and size of the nose
White - teardrop shape, long, narrow nasal apertures
Black - short, round, wide, nasal apertures
Native american/Asian traits fall in between
Prognathism
- the projection of the maxilla in front of the nasal spine
- How far in front of the base of your nose does your upper jaw extend
White = “flat face”, almost no projection
Black = more projection
Native american/Asian = smaller
width and shape of face
White and black = very narrow faces
Native american/Asian = wide faces
*Caused by forward projection of zygomatic bones (cheek bones)
eye orbits
- the socket for the eye
White = have a angular shape, almost rectangle, with a downward projection
Black = more rectangular, not tilted
Native american/Asian = round appearance
orbital border
the ring of strengthened bone along the eye orbit
things to observe in the vault for ancestry estimation
- Post bregmatic depression
- Wormian bones
- Inca bone
- Suture complexity
post bregmatic depression
- a slight concavity posterior to Bregma
- Bregma is junction of sagittal and coronal suture of skull
- Small dip from side profile view on top of skull
Wormian bones
intrasuture bones (grow in sutures do to their complexity)
inca bone
- a separation bone found at Lambda
- Very common in descendants of Incan operations
- Caused by failure of some suture formation
Suture complexity
White = sutures are not as squigled
Native american/Asian = very squigled sutures
crowding of the teeth related to ancestry
Very common in whites because jaws are not as long (prognathism)
dental arch related to ancestry
- the shape of the alveolar bone (the part that holds the teeth)
White = has parabolic shape/dental arch, narrow base, high arch, posterior shape are not parallel
Native american/Asian = elliptical shape, posterior shape are not parallel, very short dental arch
Black = teeth are more parallel, almost squared off shape
incisor shape related to ancestry
- Spatulate shaped incisors
- Shovel shaped incisors = common native american characteristic
estimating ancestry without the cranium
- Very little difference between the groups
- Only slightly reliable characteristic is femoral curvature
- white/asians = more curved
- Black = straight
metric analysis for estimating ancestry
- use ForDisc 3.0
- Takes measurements and compares to thousands of individuals
- Is hard, have to know how to do it and get good data for good results
different ways to start estimating stature
- Lay the cadaver out on the table = Soft tissue shrinkage alters estimation, Shrinkage caused by dehydration to the body
- Hang the cadaver by the ears = Can increase measurements by 2 inches, Maximizes all extension of joints etc
- Lay bones on the table = All significant bones must be present, Logistical problems of disarticulated skeletons, Difficult to reproduce in vivo intrabone spacing
Problems with stature estimation
- Mismeasurement of the living = Interobserver error
- Stature varies with time of day = You are taller in the morning
- Secular changes = We are taller than earlier generations
- Lies = People lie when asked about height and weight
Fully method to estimate stature
- Rarely used
- Uses summed heights of skull, vertebra, femur, tibia, and ankle (Has an adjustment for soft tissue)
- Accurate within ½ inch
- Problems = Time consuming, Requires several elements, Only used white males in method development
Trotter and Gleser method for estimating stature
- Can use any of the long bones = Legs more accurate than arms, requires one long bone to make estimation, best to use is the femur
- Developed on over 5000 skeletons = inclusive study
- groups differ in body proportions = Requires knowledge of sex and ancestry, Woman tend to have longer torsos and shorter legs, and opposite for men, small differences in proportions based on racial group/culture
- Age correction = 0.06 cm per year reduction after 30 years old, Your vertebral disc soften at this age because of hormonal change
Regression analysis for estimating stature
- Y = mx + b
- Plot on a graph that shows correlation
- Have to know sex and ancestry in order to use correct equation to find stature
