age estimation in fetus

Age EstimationAge EstimationGwen RobbinsGwen Robbins

Appalachian State UniversityAppalachian State University

Prenatal agePrenatal ageDifficult to know exactly when fertilization Difficult to know exactly when fertilization took placetook placeDefining gestation length in humansDefining gestation length in humans

Clinical setting: Clinical setting: 280 days from first day of LMP280 days from first day of LMPWeight 2550Weight 2550--3360g; Length 283360g; Length 28--32 cm (CRL)32 cm (CRL)Neurological and developmental maturityNeurological and developmental maturity

Embryological definition:Embryological definition:From fertilization (LMP + 14 days)From fertilization (LMP + 14 days)9.5 months or 266 days9.5 months or 266 days

Perinatal AgePerinatal AgeAge around the time of birth established by long bone lengths anAge around the time of birth established by long bone lengths and d

dental materialdental material

Means and ranges for maximum lengths of Means and ranges for maximum lengths of diaphysesdiaphyses (shafts) of major long bones at 10 lunar months (shafts) of major long bones at 10 lunar months (40 lunar weeks)(40 lunar weeks) Fazekas and Kosa (1978)Fazekas and Kosa (1978)

Mean (mm) Range

Humerus 64.9 61.6 - 70.0

Radius 51.8 47.5 – 58.0

Ulna 59.3 55.0 – 65.5

Femur 74.3 69.0 – 78.7

Tibia 65.1 60.0 – 71.5

fibula 62.3 58.0 – 68.5

Dental Development: Deciduous DentitionDental Development: Deciduous Dentition

Beginning of Mineralization (lunar weeks)

Tooth mean range

Central incisor 15 13-17

Lateral incisor 17 14-19

Canine 19 17-20

First molar 16 14-17

Second molar 19 18-20

(Sunderland et al 1987)

Perinatal AgePerinatal AgeAge around the Age around the

time of birth time of birth established by established by long bone long bone lengths and lengths and dental materialdental material

Postnatal agePostnatal age

SubSub--adults = time from birth to adulthoodadults = time from birth to adulthoodInfancy (birth Infancy (birth –– 3 years)3 years)Childhood (3Childhood (3--7 years)7 years)

•• Juvenile (beginning at 7)Juvenile (beginning at 7)•• Adolescent Adolescent

•• 1010--18 in girls18 in girls•• 1212--18 in boys18 in boys

By the wayBy the way……

Before we talk about age estimation methods for Before we talk about age estimation methods for subsub--adults and adults, we need to decide adults and adults, we need to decide ““When When does adulthood begin?does adulthood begin?””

•• we already defined adolescence aswe already defined adolescence as•• 1010--18 in girls18 in girls•• 1212--18 in boys18 in boys

•• adulthood can be defined by physical attribute or adulthood can be defined by physical attribute or physiological states independent of chronological agephysiological states independent of chronological age

•• when growth of the body ceaseswhen growth of the body ceases•• when full biological fertility is achievedwhen full biological fertility is achieved

SubSub--Adult Age Estimation Methods: Long Bone LengthAdult Age Estimation Methods: Long Bone Length

Antenatal Bone Growth

Example: Femur (Fazekas and Kosa 1978)

Age (wks) Length Distal width

12 8.5 1.9

40 74.4 19.9

Juvenile Long Bone Growth

Example: Femur (Maresh 1970)

Age Male Female (yrs) n Mean sd n Mean sd

diaphyseal length

0.125 59 86.0 5.4 68 87.2 4.3

SubSub--adult Age Estimation Methods: Long Bone Lengthadult Age Estimation Methods: Long Bone Length

Predicted Age from Regression

Perinatal: Scheuer et al 1980

Age (wks) = 0.3303 (length) + 13.5583 (ME = +/- 2.08)

Dental Age (mo)

12010896847260483624120-12

Hum

erus

leng

th (m

m)

220

200

180

160

140

120

100

80

60

40

20

0

Maresh

(1970)

Humerus INM

Late Jorwe

While you CAN establish age from growth and development, long bone length is heavily influenced by environment, can become circular

Dental Age Estimation MethodsDental Age Estimation Methods

Perhaps the most accurate methodsPerhaps the most accurate methods

Formative:Formative:crown formationcrown formationeruptioneruptionroot developmentroot development

Degenerative:Degenerative:attrition (wear)attrition (wear)colorcolorperiodontal attachmentperiodontal attachment

Histological:Histological:neonatal lineneonatal linecementumcementum

Age Estimation: Dental Formation and EruptionAge Estimation: Dental Formation and Eruption

SubSub--adult Ages of Crown and Root Completionadult Ages of Crown and Root Completion

Tooth mean MFH 63 Smith 91 LDM 93

Age of crown completion (months)

Central incisor - - 1-2.5 1

Lateral incisor - - 2.5 5

Canine 8.5 5-12 8.5 8.5-17

First molar 4 1-8.5 6 5-9.5

Second molar 8.5 5-12 9.5-11 8.5-17

Age of root completion (years)

Central incisor - - 1.5 1.1-1.6

Lateral incisor - - 1.5-2 1.5

Canine 3 2.3-3.8 3.25 2.6-2.9

First molar 2 1.3-2.5 2.25 2.6

Second molar 3 2.2-3.9 3 3

SubSub--Adults: Tooth Formation and Eruption TimingAdults: Tooth Formation and Eruption Timing

Formation Times for the Permanent DentitionFormation Times for the Permanent DentitionStage I1 I2 C P3 P4 M1 M2 M3

Female

Ci - - 0.6 2.0 3.3 0.2 3.6 9.9

Cco - - 1.0 2.5 3.9 0.5 4.0 10.4

Coc - - 1.6 3.2 4.5 0.9 4.5 11.0

Cr1/2 - - 3.5 4.0 5.1 1.3 5.1 11.5

Cr3/4 - - 4.3 4.7 5.8 1.8 5.8 12.0

Crc - - 4.4 5.4 6.5 2.4 6.6 12.6

Ri - - 5.0 6.1 7.2 3.1 7.3 13.2

R1/4 4.8 5.0 6.2 7.4 8.2 4.8 9.5 15.2

R1/2 5.4 5.6 7.7 8.7 9.4 5.4 10.3 16.2

R2/3 5.9 6.2 - - - - - -

R3/4 6.4 7.0 8.6 9.6 10.3 5.8 11.0 16.9

Rc 7.0 7.9 9.4 10.5 11.3 6.5 11.8 17.7(Smith 1991)

Age Estimation from Length of CrownAge Estimation from Length of Crown

Deciduous dentition

di1 -0.653 + (0.144 * length) +/- 0.19

di2 -0.581 + (0.153 * length) +/- 0.17

dc -0.648 + (0.2.9 * length) +/- 0.22

dm1 -0.814 + (0.222 * length) +/- 0.25

dm2 -0.904 + (0.292 * length) +/- 0.26

Permanent Dentition

I1 0.237 – (0.018 * length) + (0.42 * length2) +/- 0.21

I2 -0.173 – (0.538 * length) + (0.003 * length2) +/- 0.14

I2 0.921 – (0.281 * length) + (0.075 * length2) +/- 0.12

C -0.163 – (0.294 * length) + (0.028 * length2) +/- 0.25

M1 -0.942 – (0.441 * length) + (0.010 * length2) +/- 0.25(Liversedge et al. 1998)

Older subOlder sub--adults: Age from Skeletal Developmentadults: Age from Skeletal Development

SubSub--adult Age Estimation Methods: Epiphyseal Fusionadult Age Estimation Methods: Epiphyseal Fusion

Epiphyseal Fusion Timing

Example: Ulna

Epiphyseal center appears 5.5-7 yrs

Fusion 15-17 yrs in females

17-20 yrs in males

While age of subWhile age of sub--adults is determined by adults is determined by growth and developmental processes, growth and developmental processes, which have a predictable sequence and which have a predictable sequence and relatively short window of timing,relatively short window of timing,

Adult ages must usually be determined by Adult ages must usually be determined by degenerative processes, which are much degenerative processes, which are much more variable larger margin of errormore variable larger margin of error

Many methods for adults are sex specificMany methods for adults are sex specific

AdultAdult Age Estimation Methods: Pubic SymphysisAge Estimation Methods: Pubic Symphysis

Suchey-Brooks MethodFemale

Male

Adult Age Estimation Methods: Auricular SurfaceAdult Age Estimation Methods: Auricular Surface

Lovejoy et al 1985

Adult Age Estimation Methods: Cranial SuturesAdult Age Estimation Methods: Cranial Sutures

1. Midlambdoid 6. Midcoronal2. Lambda 7. Pterion3. Obelion 8. Sphenofrontal4. Anterior Sagittal 9. Inferior Sphenotemporal5. Bregma 10. Superior Sphenotemporal

Composite scores are obtained by summing scores for five “vault” sites and five “lateral-anterior” sites.

0 = open: There is no evidence of any ectocranial closure1 = minimal closure: Some closure has occurred. Score is assigned to any minimal to moderate closure, i.e. from a single bony bridge across the suture to about 50% synostosisat the site.2 = significant closure: There is a marked degree of closure but some portions of the site is still not completely fused.3 = complete obliteration. The site is completely fused.

Age Estimation Methods: Cranial SuturesAge Estimation Methods: Cranial Sutures

Age Estimation Methods: Age Estimation Methods: SternalSternal End of the Right 4End of the Right 4thth RibRib

Dental Age Estimation MethodsDental Age Estimation Methods

Perhaps the most accurate methodsPerhaps the most accurate methods

Formative:Formative:crown formationcrown formationeruptioneruptionroot developmentroot development

Degenerative:Degenerative:attrition (wear)attrition (wear)colorcolorperiodontal attachmentperiodontal attachment

Histological:Histological:neonatal lineneonatal linecementumcementum

Adults: AttritionAdults: Attrition

Using Attrition to Estimate Age (Brothwell 1981)Using Attrition to Estimate Age (Brothwell 1981)

Using Attrition to Estimate Age (Miles 1962)Using Attrition to Estimate Age (Miles 1962)

Cementum AnnulationsCementum Annulations