DEPARTMENT OF ANATOMICAL SCIENCES
AN321 - FORENSIC OSTEOLOGY
AGE ESTIMATION FROM THE SKELETON
W. B. Wood
The University of Queensland
A forensic osteologist may be requested to carry out a skeletal age estimation in the following circumstances:
a) Medicolegal Purposes:
when the age of a living victim or of an accused person is unknown and
particularly when it involves such questions as:
- jurisdiction of the adult or children's court
- age of consent, carnal knowledge
- age of abandoned infants or children
b) Forensic Purposes:
- establishing foetal or neonatal age at death
- estimating age at death of unidentified juvenile or adult bodies or skeletal
- sorting and identifying commingled remains eg in mass burials or mass
disasters involving severe mutilation or burning of remains etc.
METHODS OF AGE ESTIMATION
The methods utilised depend on whether one is dealing with a juvenile or an adult.
1. FOETAL & PERINATAL AGE ESTIMATION:
In the foetus or new-born infant, age estimation is best determined from long bone lengths and the appearance of ossification centers (Fazekas & Kosa 1978, Kosa 1989, Scheuer et al 1980). Racial variations do occur due to genetic and nutritional factors and must be taken into account where low birthweights and reduced body size are the norm.
2. JUVENILE AGE ESTIMATION:
In juvenile skeletal material, age estimates are best determined from the degree of dental formation and eruption (Moorrees et al 1963a & 1963b, Demirjian et al 1973). In the absence of a cranium or mandible with teeth, long bone lengths and epiphysial union observations provide the best estimates.
Marked sex differences do occur and hence sex should be determined if at all possible before estimating age from the bone lengths or epiphysial union observations. If sex is unknown then appropriate adjustments must be made to the estimated age and age-range to make allowance for the possibility that the skeleton may be derived from either sex.
The best summaries with tabular data are provided by Stewart (1979) and Krogman and Iscan (1986). Ubelaker (1987) gives a good overview of the whole topic.
3. ADULT AGE ESTIMATION
In recent years a battery of ageing methods based on joint surface metamorphoses has become available. The best known of these are the pubic symphysial methods of McKern and Stewart (1957), Gilbert and McKern (1973), Katz & Suchey (1986), Suchey,Brooks & Katz (1988); the auricular surface method of Lovejoy et al.(1985); and the costochondral junction method of Iscan et al. (1984 & 1985). The McKern & Stewart method is best used for males under 40. Over that age the Katz & Suchey method is probably more accurate. The claimed accuracy for these methods varies between 5-10yrs sd.
The histomorphometry of cortical bone tissue in the limb long bones, ribs and mandible also has been shown to vary in a systematic fashion with increasing age, and regression formulae for age prediction have been developed with a claimed predictive accuracy of +/- 5 years (Kerley 1965, Kerley & Ubelaker 1978). However the techniques are highly specialised and require the sectioning or coring of the sample bones.
Two relatively recent papers on age estimation from cranial suture closure (Meindl et al 1985, Mann et al 1987) have rejuvenated interest in this largely discredited method of age estimation but have yet to be proven reliable.
Radiological changes (cortical thickness & density, trabecular patterns and the size and extent of the medullary cavity) particularly in the humerus, clavicle and femur also prove useful in gross age estimation where other methods are unavailable or considered inappropriate (Schranz 1959, Walker & Lovejoy 1985). They help to distinguish the young adult from middle aged and elderly individuals.
In the absence of other age markers in the adult skeleton the degree of development of vertebral osteoarthritis may give a rough guide to the individuals age (Stewart 1958).
In precontact Aboriginal skeletal material or in Aborigines still living in a largely tribal environment, the degree of wear on the molar teeth (dental attrition) is extremely useful for relative ageing (Brothwell 1981).
Brothwell D.R. 1981 Digging up Bones. British Museum of Natural History.
Demirjian A, Goldstein H and JM Tanner 1973 "A new system of dental age assessment." Human Biology 45 (2):211-227
Fazekas IG & F Kosa 1978 Forensic Foetal Osteology. Akademiai Kiado, Budapest
Gilbert BM & TW McKern 1973 "A method for ageing the female os pubis." AJPA 38:31-38
Iscan MY, Loth SR & RK Wright 1984 "Age estimation from the rib by phase analysis: white males." JFS 29:1094-1104
Iscan MY, Loth SR & RK Wright 1985 "Age estimation from the rib by phase analysis: white females." JFS 30:853-863
Katz D & JM Suchey 1986 "Age determination of the male os pubis." AJPA 69:427-435
Kerley ER 1965 "The microscopic determination of age in human bone." AJPA 23:149-163
Kerley ER & DH Ubelaker 1978 "Revisions in the microscopic method of estimating age at death in human cortical bone." AJPA 49:545-546
Kosa F 1989 "Age estimation from the foetal skeleton." In Age Markers in the Human Skeleton. Iscan MY (Ed), C.C. Thomas, Springfield
Krogman WM & MY Iscan 1986 The Human Skeleton in Forensic Medicine. C.C. Thomas, Springfield
Lovejoy CO, Meindl RS, Pryzbeck TR & RP Mensforth 1985 "Chronological metamorphosis of the auricular surface of the ilium: A new method for the determination of adult skeletal age at death." AJPA 68:15-28
Mann RW, Symes SA & WM Bass 1987 "Maxillary Suture Obliteration: aging the human Skeleton based on intact or fragmentary maxilla." J For Science 32(1):148-157
McKern TW & TD Stewart 1957 "Skeletal age changes in young american males, analysed from the standpoint of identification." Headqu QM Res and Dev Command, Tech Rep EP-45 Natick, MA
Meindl RS & C Owen Lovejoy 1985 "Ectocranial suture closure: a revised method for the determination of skeletal age at death based on the lateral-anterior sutures." AJPA 68:57-66
Moorrees CFA, Fanning EA & EE Hunt 1963a "Formation and resorption of three deciduous teeth in children." AJPA 21:205-213
Moorrees CFA, Fanning EA & EE Hunt 1963b "Age formation stages for ten permanent teeth. J Dent Res 42:1490-1502
Scheuer JL, Musgrave JH & SP Evans 1980 "The Estimation of Late Foetal and Perinatal Age from Limb Bone Length by Linear and Logarithmic Regression." Annals Hum Biol 7 (3):257-265
Schranz D 1959 "Age determination from the internal structure of the humerus." AJPA 17:273-277
Stewart TD 1958 "The Rate of Development of Vertebral Osteoarthritis in American Whites and its Significance in Skeletal Age Identification." The Leech 28(3-5):144-151
Stewart TD 1979 Essentials of Forensic Anthropology. C.C. Thomas Publishers
Suchey JM, Brooks ST & D Katz 1988 "Instructional materials accompanying female pubic symphyseal models of the Suchey-Brooks system." Distributed by FRANCE CASTING (Diane France, 2190 West Drake Road, Suite 259, Fort Collins, Colorado 80526
Ubelaker DH 1987 "Estimating age at death from immature skeletons." JFS 32:1254-1263
Walker RA & CO Lovejoy 1985 "Radiographic changes in the clavicle and proximal femur and their use in the determination of skeletal age at death." AJPA 68:67-78