Estimation of Age at Death: The Deteriorating Skeleton

Estimation of Age at Death: The Deteriorating Skeleton Screencast 1 ➢ Adults - Once skeletal growth has ceased (approximately mid-20’s) other methods have to be used to estimate age - Several structures in the skeleton undergo changes over time → deterioration - Changes in adults much more subtle compared to changes in subadults - Four osteological features provide accurate estimates of age: o Symphyseal surface (pelvis) o Auricular surface (pelvis) o Sternal rib ends o Cranial sutures ➢ Symphyseal Surface - Pubic Symphysis o Located in the midline where the two innominates meet - Pubic faces alter over time (Todd, 1920) and changes can be used to determine age at death - Todd described 10 stages of change which have more recently been modified - Features examined are: o Pubic face o Ventral and dorsal margins o Upper and lower extremities o Ossific nodules ➢ Pubic Face - Pubic face undergoes several changes with age - Young individuals = ridges separated by furrows across the surface (a) - Furrows fill in over time – posterior → anterior direction (b) - Face becomes flat with granular appearance (c and d) - Old age = face pitted and eroded (e) ➢ Ventral Margin - Ventral = on the front - AKA the anterior margin → has two characteristics that develop over time: o Bevel (sloping surface or edge) o Rampart - Young = ventral margin forms a right angle with the pubic face (a) - Ridges degenerate over time and furrows fill in → margin spreads onto the pubic face - Corner between ventral margin and pubic face changes from sharp → smooth (b) o Margin bevels onto the pubic face - Bone is deposited on the ventral bevel over time → forms a rampart - Ventral margin once again takes the form of a right angle (c) - Rampart starts at the bottom and spreads upwards - Later it starts at the top and moves downwards - Two ramparts eventually meet (d) ➢ Upper and Lower Margins - Also referred to as the ‘extremities’ - Young = extremities not easily distinguished (1) - Older = margins become more definer o Lower extremity becomes defined first (2), followed by the upper extremity (3) ➢ Symphyseal Surface - Four other features that appear with increasing age: o Ossific nodules (a) – lumps of bone appearing early adulthood o Rim (b) – formed by appearance of the extremities and margins o Lipping – ventral and dorsal margins curl towards o Ligamentous outgrowths – ossified ligament on the ventral border ➢ Suchey-Brooks Method - Suchey-Brooks is the most common method used by anthropologists for determining age - The amount of change seen in the pubic symphasis can be divided into six stages: Phase 1 = Age range of 15 – 23 years ➢ Problems with the Suchey-Brooks Method - Phase 3 = 21 – 53 years (female) or 21 – 46 years (male) o Need to know sex in order to determine age - Age ranges increase as we get older o Females in Phase 1 = 15 – 24 years of age o Females in Phase VI = 42 – 87 years of age Screencast 2 ➢ Auricular Surface of the Innominate - Bones of the sacroiliac joint (sacrum and innominate) change over time - Correlate these changes over time = estimate age at death - Negative: changes are subtle so hard to identity - Positive: bone survives events that destroy other parts of the skeleton - Three areas used to estimate age: o Auricular surface: where sacrum and ilium articulate o Apex: top corner of the auricular surface o Retroauricular surface: area behind the auricular surface that varies in shape and can be wavy - Features that change over time include: o Transverse organisation of the auricular surface (how the bone is arranged across the joint) ▪ Young individuals = billows (1) ▪ Billows begin to fill in over time – replaced by striae (2) ▪ Elderly = striae eventually lost (3) o Texture of the bone ▪ Young individuals = bone granular/smooth/dense ▪ Bone becomes more coarse as we age (sandpaper) ▪ All smoothness lost as bone degenerates o Increase in porosity ▪ Young individuals = small perforations in bone (microporosity) ▪ Perforations become large as we age (macroporosity) • Can reach 10 mm in diameter - The condition of each of these five features can be used to determine age at death: ➢ The Retroauricular Area - Young individuals = bone smooth and youthful looking (1) - Becomes coarse as we age (2) - Older individuals = exhibits osteophytes and outgrowths (3) o Osteophytes = bony projections that form along margins ➢ The Apex ➢ Sternal Rib Ends - End of the ribs that join to the sternum (via cartilage) change over time - Age increases – tendency for cartilage to ossify o Bone-like structures produced in and around cartilage - Observed in costal cartilage where ribs connect - Results in changes in the ribs end - Right fourth rib most studied but it appears on either side for ribs 3 – 10 - Four features change over time: o Surface bone (a) – smooth cortical bone → granular → porous o Surface contour (b) – billows → flat → indented (V-shaped changed to Ushaped) o Rim around the sternal end (c) – no rim → rim begins to form → thinner with jagged edge o Rim contour (d) – straight → wavy → fingers of bone ➢ Cranial Sutures - Three areas of the skull where sutures close according to a rough timetable o Ectocranium (outside of the skull) o Endocranium (inside the skull) o Palate (top of the mouth) ➢ Ectocranial Sutures - Four stages of closure in cranial bones a) Open – no evidence of closure; gap between bones still visible b) Minimal – closing of the gaps in less than 50% of the suture c) Significant – more than 50% fusion between bones; small areas still open d) Obliteration – complete fusion with no gaps; may appear as a line ➢ Endocranial Sutures - Examination of the sutures on the endocranium o Examine coronal (a), sagittal (b) and lambdoid (c) sutures o Amount of fusion is only a general indicator of age - Three broad categories: o Early adulthood (20 – 34 years) • Minimal closure at all 3 sites o Middle adulthood (35 – 49 years) • Significant closure at all 3 sites o Late adulthood (50+ years) • - Obliteration at all 3 sites Cranial suture closure is a poor indicator of age ➢ Palatal Sutures - Only able to place the individual in one of three broad categories (young, middle, late adulthood) - Three sutures used to estimate age: o Incisive (IN) • Only seen in infants and children o Median palatine • Divided into anterior (AMP) and posterior (PMP) • Partial closure in young adults • Complete PMP closure middle adult (AMP partial) o Transverse palatine (TP) • Partial closure in young adults • Complete closure in middle adults