Variation of the degree of sacral vertebral body fusion in adulthood in two European modern skeletal collections

Abstract

A new standardized scoring method was used to study age variation of the degree of fusion of the ventral face of the sacral vertebral bodies (SVF) in 904 adult skeletons of both sexes from two identified modern samples (20th c.): Frassetto collections (Museum of Anthropology, University of Bologna, Italy) and Colecção de Esqueletos Identificados (Museum of Anthropology, University of Coimbra, Portugal). SVF was scored for each fusion site (between S1 and S2, etc.) on a four-stage scale, from nonfusion (Degree 0) to complete fusion (Degree 3). Inter-observer error of 1.2% suggested good reproducibility. The data were analyzed according to age, sex, and population. There were sex and population differences only in young adults (20-34 years). Sex differences in SVF were present in both collections, with females displaying earlier fusion than males. The differences occurred until 35 years, after which there was a generalized prevalence of completely fused sacra. Population differences were observed for males, with the Sassari men showing later sacral vertebral fusion than the Coimbra men. Our study suggests that incompletely fused sacra can help in distinguishing young adults from old adults regardless of sex and population.

Sacral fusion as an aid in age estimation

“…First, we applied the recommendations of Belcastro et al [10] to our Lisbon sample. It is important to state that the scoring system used by these authors differs slightly from that used in the present study.…”

“…Recently, Belcastro et al [10], reported the state of fusion of the sacral vertebrae in two documented collections (Sassari and Coimbra). This study widened the age range of the military sample from McKern and Stewart [9], and included a female sample.…”

“…Two age variables were used, AGE1, a 5-year interval grouping, and AGE2, the broad age groups defined by Belcastro et al [10] with an additional subadult age group: SB (subadults, <20 years old), YA (young adults, 20-34 years old), MA (middle adults, 35-49 years old), OA (older adults, over 50 years old). The first variable provides detailed information on the variability of sacral fusion in relation to age while the second one is commonly used in bioarchaeological studies [14].…”

Épidémiologie de la maladie dégénérative vertébrale dans des séries ostéologiques documentées. Proposition d’une nouvelle méthode de cotation et première application aux articulations interapophysaires lombaires

“…Celles-ci sont constituées par la collection de Schoten [53,54] conservée au Muséum royal d'histoire naturelle de Bruxelles, Belgique ; et la collection Frassetto [55,56] constituée des séries de Bologne et de Sassari, conservée au musée d'anthropologie de Bologne en Italie. Cet échantillon documenté est réparti de manière équivalente et équilibrée par âge (cinq classes) et par sexe (sex-ratio : 1:1).…”

“…Elles permettent d'observer de manière claire une augmentation de la moyenne du score en fonction des classes d'âge. Cette constatation est moins nette chez les femmes entre les classes [40][41][42][43][44][45][46][47][48][49] ans et [50][51][52][53][54][55][56][57][58][59] ans, où l'on remarque une diminution de la moyenne. Globalement, les femmes sont plus sévèrement atteintes que les hommes, principalement pour les classes [30][31][32][33][34][35][36][37][38][39] ans et [40][41][42][43][44][45][46][47][48][49] ans (respectivement 7,00 et 9,00 de moyenne contre 4,37 et 7,00 chez les hommes).…”