1 - Age Estimation of the Human Skeleton Flashcards
What forms the basis for age estimation in the human skeleton?
1) Age results in linear increases in bone dimensions
2) Appearance and fusion of ossification centres occurs at similar points in development
3) Predictable / averaged eruption of teeth, their loss and also their replacement
What features can help identify juvenile bones?
1) Size
2) Proportions
3) Texture (undulating, granular articulating surfaces)
4) Fusion - or lack thereof
What 3 skeletal features provide accurate age estimation in fetal / infant skeletons?
Femur length (in utero)
Dental development (infant)
Bone fusion
What are 5 features of deciduous teeth?
Small
Constricted neck
Bulging crown
Roots of ANTERIOR teeth are elongated.
Roots of POSTERIOR teeth are flared.
In the context of ageing, which 3 categories of fusing bones are useful age estimation tools up until early adult life?
Midline fusions:
- Mandible (6-9 months)
- Frontal bone (1-2 years)
Epiphyseal fusion:
- Femur / hip bone (13-20 years) [puberty]
Late-fusing centres
- Medial clavicle
- Sacral bodies
What 3 aspects make up dental development?
Crown formation
Root formation
Eruption
What are the chronological changes that occur at the medial surface of the pubic symphysis?
Adolescent
Increasing age
Adult
Adolescent:
- Horizontal grooves
- No margin
Increasing age:
- Infilling of grooves
- Thicker margin
- Rim around joint surface
Old age:
- Irregular margin
- Pitted / porous surface
Which two groups of individuals developed pubic symphysis age estimations?
Suchey and Brooks
Todd, McKern and Stewart
Describe the functionality of Suchey and Brook’s age estimation method?
6 stages of sequential increasing age
Variation within each stage is accounted for with ‘early’ and ‘late’ examples.
**Separate age estimations exist for male and female.
Each phase in Suchey and Brooks has variation in age estimation. What happens to this variation with increasing phase number?
Increases.
Greater scatter, and becomes more positively skewed.
What age ranges are covered in Suchey and Brook’s symphysis age estimation tool?
10-80 years
Why might the data of higher phases within Suchey and Brooks have occurred?
Mismatch between chronological age and skeletal age - greater extent.
Environmental factors, lifestyle etc.
What two reasons explain why the first molar usually more worn in comparison to the third molar?
1) Eruption occurs 6 years apart.
M1 = 6 M2 = 12 M3 = 18
2) Usually a greater occlusal load on M1
What 3 factors can also rate of molar wear?
Diet
Disease
Non-dietary usage
What 3 causes of dental wear exist? And what is each one?
Attrition - inter-tooth contact
Abrasion - hard particulates
Erosion - chemical dissolution
What two microscopic dental markers within enamel can provide estimation into age at death?
Perikymata on enamel
Striae of retzius
How frequently do striae of Retzius occur?
7-8 day intervals
In bones, what radiological finding can show periods of halted growth?
Harris lines
Periods lacking in tooth development results in what finding?
Linear enamel hypoplasia
What type of process is most commonly used to determine age of adult skeletons?
Degenerative processes
What issue occurs with age estimation and increasing age however?
For what reasons?
Becomes less accurate with increasing age.
Greater variability due to factors such as diet, physical activity, trauma and disease.
What 4 features are analysed when age-estimating the auricular surface of the ilium?
1) Transverse organisation
2) Granularity
3) Porosity
4) Joint surface margin
What is the Spitalfield’s Known-age collection?
Sum of 5 scores to give a total score and subsequent age estimate.
What 5 scores are used within the revised auricular surface method?
1) Transverse organisation
2) Surface texture
3) Microporosity
4) Macroporosity
5) Apical changes
What ages do the skull fontanelles close in the infant?
1) Posterior: 3-6 months
2) Anterolateral: ~6 months
3) Posterolateral: 6-12 months
4) Anterior: 12-36 months
What two methods of age-estimation are there for assessing molar wear?
Mile’s molar wear
Brothwell
What changes are visible in the trabeculae of the humeral / femoral head that occur with ageing?
Cortical thinning
Trabecular cavitation
Suchey and Brooks has what feature that caters for the whole population?
Male and female ageing standards.
What age does S1-S2 fusion occur?
25-30 years old
What stages of clavicular fusion are there, and what ages do they occur?
Not fused: <18
Partially: 16-21
Fused: 24-29
Name 4 microscopic methods of age estimation
Root dentine transparency
Cementum growth
Osteon accumulation
Amino acid racemisation
What variables should be considered when undergoing age-estimation?
Malnutrition
Infection
Nutrition / infection interplay
Taphonomic factors
What are 3 age-progressive diseases that can act as indirect indicators of longevity?
Osteoporosis
Osteoarthritis
Paget’s disease
What is osteoporosis?
Loss of bone mineral
What is osteoarthritis?
Degeneration of joint surfaces
What is paget’s disease?
A disease of bone remodelling / recycling process.
How does root dentine transparency work?
Microscopic tubules in the dentine are progressively infilled.
Start at root apex.
Ratio then made between translucent:length of dentine
What occurs in amino acid racemisation for it to be used as an age-estimation method?
Racemisation of amino acids in COLLAGEN from 100% L-isomer into 50% D and 50% L-isomers.
What factor increases rate of racemisation?
Temperature
Define racemisation
Conversion of optically active compound into optically inactive compound.
Advanced Glycation end products are made of what?
Post-translational non-enzymatic modifications of collagen in vivo.
What changes occur in the sternal ends of the upper ribs with ageing?
In young?
In old?
Young:
- Smooth
- Straight-walled
- Slightly indented
OLD:
- Deeper
- Wider
- Scalloping of walls.
- Irregularity of margins
What is a potential limitation to having modern standards of age-estimation?
Cultural, healthcare and evolutionary changes - may not mimic the patterns of growth / ageing in the time of the skeletal specimen.
What sign is Cribra orbitalia and what is it a marker of?
Active healing in orbital roof.
Anaemia
Periostitis is a marker of what disease presence?
Infection
