Young-Adult Age from the Pubic Symphysis and Auricular Surface

The six Suchey-Brooks phases are defined by the morphological state of the symphyseal face as observed on the intact pubic bone, with reference to plaster casts (the Suchey-Brooks cast sets were commercially produced and distributed to training programmes) and to the illustrated criteria published in the accompanying paper.

Phase 1 describes a billowing symphyseal face with distinct ridges and furrows running horizontally across the surface, with no dorsal plateau and no delimitation of the oval or pointed ventral arc. This surface is typical of individuals in their mid-to-late teens and early twenties. In the male reference sample, Phase 1 age ranges from 14 to 25 years with a mean of 19.4 years (standard deviation 3.9 years).

Phase 2 shows the ridges beginning to smooth, with the dorsal plateau forming on the upper half of the surface and the ventral arc beginning to delimit. The horizontal billowing is still present in the lower half. In males, Phase 2 ranges from 15 to 33 years with a mean of 25.0 years.

Phase 3 shows a more complete dorsal plateau with some ossific nodules at its margins, continued ridge reduction, and the ventral arc more clearly defined. In males, Phase 3 ranges from 19 to 48 years with a mean of 32.4 years.

Phase 4 shows the symphyseal face substantially complete, the dorsal plateau forming a distinct rim on the dorsal border, a ventral rampart beginning to form, and the surface becoming smoother overall. In males, Phase 4 ranges from 22 to 70 years with a mean of 39.5 years.

Phase 5 shows a fully formed and complete oval or pointed ventral arc, a complete dorsal plateau, a distinct rim around most of the symphyseal face, and a surface that is beginning to show signs of breakdown with some porosity. In males, Phase 5 ranges from 28 to 78 years with a mean of 50.0 years.

Phase 6 shows extensive breakdown of the symphyseal rim with erosion, pitting, and porosity of the surface. The face appears irregular, rough, and degraded. In males, Phase 6 ranges from 34 to 86 years with a mean of 61.7 years.

The original Todd system was derived almost entirely from males; the McKern-Stewart Korean War sample was exclusively male. Using male-derived standards for female remains generates systematic errors, generally in the direction of underestimating age in younger females and overestimating age in older females, because female symphyseal degeneration follows a somewhat different trajectory linked to parity (the number of pregnancies), hormonal influences, and differences in symphyseal anatomy.

The Suchey-Brooks 1990 paper was the first to provide fully sex-stratified standards from a large reference sample: 1,108 males and 273 females from the Los Angeles County coroner's autopsies, with documented ages at death. The smaller female sample was a limitation the authors acknowledged. The female means and age ranges for each phase are slightly different from the male means, with female Phases 4 through 6 skewing somewhat younger on average, though the overlap between phases and between sexes is extensive.

The key practical consequence is that the forensic anthropologist must first assess the sex of the pubic bone (using the ventral arc and sub-pubic concavity, which are sex-specific regardless of age) before applying any phase-to-age conversion. Applying the male Suchey-Brooks tables to a female pubic bone, or vice versa, produces an incorrect age estimate. In the field and in the laboratory, this requires that sex estimation and age estimation on the pelvis be performed as a coordinated, interdependent analysis.

For populations outside the Los Angeles County reference sample, published validation studies have assessed whether the Suchey-Brooks phase-to-age conversion is transferable. The Igarashi 2005 Japanese revision, derived from a Japanese forensic autopsy sample, found that Phase-to-age correspondence differed from the Suchey-Brooks norms, with Japanese individuals showing somewhat slower symphyseal degeneration on average and therefore older mean ages within phases 3 through 5. This finding has implications for applying the Suchey-Brooks tables to East Asian remains. For South Asian populations, comparable validation data are sparse; Indian forensic anthropology departments at AIIMS and several state medical colleges have published small-sample studies but a definitive Indian validation dataset comparable in scale to the Los Angeles County sample does not yet exist.

In Korean cohort studies (Jo and Oh 2020, Journal of Forensic and Legal Medicine), Phase 4 mean age for males was approximately 42 years compared to the Suchey-Brooks male mean of 39.5 years, and Phase 5 was approximately 53 years compared to 50.0 years. These differences suggest that applying Suchey-Brooks tables to Korean remains may slightly underestimate age in the middle adult phases.

C. Owen Lovejoy and colleagues published the auricular surface eight-phase scoring system in the American Journal of Physical Anthropology in 1985, derived from the Libben Site skeletal population (an Ohio Native American archaeological collection of approximately 1,300 individuals) supplemented by a small cadaveric sample. The auricular surface (named for its resemblance to the shape of the external ear) is the articular face on the posterior medial ilium that participates in the sacroiliac joint. It is covered by fibrocartilage in life and shows progressive degenerative changes similar in logic to those of the pubic symphysis, though the specific morphological criteria are different.

Lovejoy's eight phases describe a progression from a finely granular surface texture with distinct transverse organisation and no porosity in young adults (Phases 1 through 4, covering roughly 20 to 45 years) through progressively coarser surface texture, loss of transverse organisation, microporosity, and macroporosity in older adults (Phases 5 through 8, covering roughly 40 to 60 and beyond). The system also scores the retroauricular area (the non-articular region posterior to the auricular surface), which shows its own progressive changes including activity modification, formation of activity ridges, and eventual fusion or coalescence.

The Lovejoy auricular surface method has two properties that make it particularly valuable for forensic casework. First, the ilium is often better preserved than the pubic bone in fragmentary or commingled remains: the ilium is more massive, more likely to survive taphonomic damage, and more likely to be recovered in a mass-disaster context. Second, the auricular surface degenerative changes extend into the older adult range more gradually than the pubic symphysis, where Phase 6 (the last assessable phase) can appear as early as the mid-thirties in some individuals. The auricular surface therefore provides a signal, however imprecise, in the over-60 range where the pubic symphysis offers little additional discrimination.

A key limitation of the Lovejoy system is its derivation from a single archaeological population with estimated ages (since the Libben site individuals did not have documented birth records). The estimated ages were themselves derived from a combination of the pubic symphysis, dental wear, and cranial suture closure, creating a circularity problem: the auricular surface phases were calibrated against ages estimated by methods that share some of the same biological variables. This limitation was acknowledged by Lovejoy and has been addressed, though not entirely resolved, by subsequent revisions.

Jo Buckberry and Andrew Chamberlain published a five-trait composite revision of the auricular surface method in the American Journal of Physical Anthropology in 2002, derived from the Spitalfields Collection (a documented skeletal collection from a London church crypt, with individuals who died between 1729 and 1852 and whose ages at death are documented in burial records). The Spitalfields Collection is one of the very few documented collections available for calibrating adult skeletal age methods in Britain, and the Buckberry-Chamberlain study was an important methodological advance because it used a documented rather than an estimated reference sample.

The five traits scored are: transverse organisation of the auricular surface (scored 1 to 3), surface texture (scored 1 to 5), microporosity (scored 1 to 3), macroporosity (scored 1 to 3), and apical change at the superior apex of the auricular surface (scored 1 to 3). The total composite score ranges from 5 to 17. Each composite score value corresponds to a median age and interquartile range derived from the Spitalfields reference individuals.

The Buckberry-Chamberlain system has several advantages over the original Lovejoy eight-phase system. The trait-by-trait scoring approach reduces inter-observer variability by making the assessment more explicit. The documented reference sample removes the circularity problem in the Lovejoy calibration. And the conversion from composite score to age via an ordinal scale makes the uncertainty more transparent.

The limitation of the Buckberry-Chamberlain system is the size and demographic character of the reference sample. The Spitalfields collection, while documented, represents eighteenth and early nineteenth century Londoners of predominantly British descent. Generalisation to non-European populations requires caution, and the sample sizes within individual composite score categories are small, producing wide confidence intervals on the median age estimates for several score values.

1. Recover and inventory the pelvis
   Confirm which pelvic elements are available: pubic bones (for Suchey-Brooks), ilium with auricular surface (for Lovejoy/Buckberry-Chamberlain), sacroiliac joint surface on the sacrum. Document preservation quality and any taphonomic damage to articular surfaces.
2. Estimate sex first
   Apply the Phenice triad (ventral arc, sub-pubic concavity, ischiopubic ramus ridge) and the greater sciatic notch score to determine sex before age assessment. Sex-specific age tables must match the sex determination; combining female morphology with male age tables produces incorrect estimates.
3. Score the pubic symphysis (if available)
   Apply the Suchey-Brooks six-phase criteria to the symphyseal face. If cast sets are available, compare directly. Assign the phase and record the sex-specific mean and full age range (not the mean alone) from the published tables.
4. Score the auricular surface (if available)
   Apply either the Lovejoy eight-phase holistic system or the Buckberry-Chamberlain five-trait composite. For the BC system, score each of the five traits separately, sum to a composite score, and convert using the published composite score to age table.
5. Combine estimates and apply Bayesian reasoning
   If both methods are available, combine the two age distributions. Where they overlap, the overlap defines the most probable range. Where they diverge, investigate whether taphonomy, parity changes, or pathology explain the discordance. Note any conditions (osteitis pubis, inflammatory arthritis, prior pregnancy) that may have altered the expected trajectory.
6. Report with full uncertainty
   State the phase score and age range from each method separately before giving the combined estimate. Report the widest defensible range, not a compressed estimate. In the UK Crown Court, the US federal courts, and in ICTY-style tribunal testimony, the range and its basis are more important than a false precision point estimate.

The most common error in forensic anthropological age testimony is compression: presenting a shorter age range than the method's reference data actually support, in order to appear more useful to the investigating authority or the court. This error is professionally serious and can be case-determinative in the wrong direction. An investigator who is told that remains are from a person aged "35 to 45 years" when the method actually supports "22 to 70 years" may unnecessarily exclude potential decedents who fall in the wider range.

The documented accuracy of the major adult age methods is as follows. For the Suchey-Brooks pubic symphysis at its most precise phase (Phase 1), the male 95 per cent confidence interval spans roughly 14 to 29 years, a 15-year window. At Phase 4, the 95 per cent interval spans roughly 22 to 70 years, a 48-year window. For the Buckberry-Chamberlain auricular surface composite, similar window widths apply, with the added complexity that the documented reference sample is small, producing wider confidence intervals on the per-score-level age estimates.

Several Bayesian approaches have been developed to improve the precision of adult age estimation by incorporating prior information about the likely age distribution of the population from which the individual is drawn. The ADBOU transition-analysis software (Boldsen, Milner and colleagues, 2002; updated versions through 2015) combines multiple skeletal indicators, applies a Bayesian framework with an adjustable prior age distribution, and produces a posterior probability distribution over age. This approach is covered in detail in the following topic on older-adult methods, but it is relevant here because the same framework can be applied to pubic symphysis and auricular surface scores.

The admissibility implications of the wide accuracy envelope are jurisdiction-specific. In the United Kingdom Crown Court, forensic anthropological age testimony is assessed under the Criminal Procedure Rules, which require expert witnesses to state the limits of their expertise and the range of their conclusion. The BSA 2023 guidance on forensic science in criminal proceedings reinforces this: an expert who presents a false precision age estimate without disclosing the underlying range may be found to have exceeded their remit. In the United States, Daubert and Rule 702 require that the expert testify to the scientific validity of the method and its known error rate; for Suchey-Brooks and auricular surface methods, the error rate is large and must be disclosed. In tribunal contexts including the ICTY and ICC, forensic anthropologists have testified to wide age ranges and the tribunals have accepted them, using the ranges as part of victim identification rather than as precise biographical data.

The Los Angeles County source of the Suchey-Brooks reference sample is itself a forensic context: the 1,225 autopsy individuals whose pubic bones formed the reference collection were individuals who died in LA County between approximately 1977 and 1990 and whose ages were documented on death certificates. The diversity of that population, spanning a wide socioeconomic and ethnic range, is part of what makes the resulting tables more robust for North American casework than earlier hospital-cadaver-based references.

The ICTY (International Criminal Tribunal for the former Yugoslavia) Srebrenica excavations, conducted from 1996 onward under the direction of the Physicians for Human Rights forensic team and subsequently by ICTY-contracted archaeologists and anthropologists, involved the age estimation of skeletal remains from the largest single-event massacre in Europe since World War II. Approximately 8,000 Bosniak men and boys were killed in July 1995. The pubic symphysis was one of the primary age indicators applied by the forensic anthropology team, in combination with auricular surface assessment and other skeletal indicators. Age estimates from the skeletal remains were used to support identification of individual victims and to document the demographic pattern of the killings. Published reports from the ICTY work cite the Suchey-Brooks and Lovejoy systems as the standard reference frameworks.

The Casey Anthony case in the United States (2011) involved skeletal remains of a two-to-three-year-old child, placing it firmly in the sub-adult dental and epiphyseal range rather than the adult symphysis methods. It is cited here as a contrast case: the forensic anthropological age testimony in that case was focused on deciduous tooth root resorption and early permanent tooth development, not on symphysis morphology, illustrating the clean methodological transition that occurs at the sub-adult to adult boundary.

Indian forensic anthropology casework involving the pubic symphysis has been reported primarily through AIIMS Forensic Medicine and Toxicology publications. The Nithari killings casework (Noida, 2006-2007), in which skeletal remains of multiple victims were recovered from a residential site, involved biological profiling including age estimation. The age ranges derived from symphyseal and auricular surface assessment in that case were consistent with the victim demographic information recovered through parallel investigation.

The Igarashi 2005 Japanese auricular surface revision, published in the American Journal of Physical Anthropology, analysed 169 individuals from a documented Japanese forensic autopsy series and found that the auricular surface changes progress more slowly in Japanese individuals than in the Spitalfields (British) reference. Japanese individuals in the Igarashi series showed auricular surface characteristics typically assigned to younger phases in the Lovejoy and Buckberry-Chamberlain systems, even at confirmed ages in the fifth and sixth decade. The practical correction is to add approximately two to five years to the Buckberry-Chamberlain composite score estimate when the individual is of Japanese or East Asian ancestry.

The Korean cohort study by Jo and Oh (2020) using a documented forensic autopsy sample found similar directional differences for the pubic symphysis: Korean individuals showed slightly slower symphyseal degeneration compared to the Los Angeles County Suchey-Brooks reference, particularly for phases 3 through 5. The authors proposed population-specific phase-to-age conversion tables for Korean remains.

For Indian populations, the situation is methodologically similar to the Korean and Japanese situation: the Suchey-Brooks norms are drawn from a population with a different demographic history, and systematic validation in Indian documented samples is needed to confirm whether the LA County phase-to-age tables apply without bias correction. In the absence of a comprehensive Indian validation dataset, the working recommendation from Indian forensic anthropology practitioners (including the AIIMS Forensic Medicine departments) is to report the full Suchey-Brooks range without adjustment, while noting in the report that the reference population differs from the Indian context and that population-specific data are not yet available at sufficient scale to quantify the bias.