No abstract

An extensive (n = 739) sample of well-documented male pubic bones was examined for age-related features. Using the traditional aging methods, Todd's system was found to over-age and both the Todd and the McKern-Stewart systems did not account for age variability seen in advanced pubic bone patterns. Based on a 5-year interobserver error study, certain categories in each system were collapsed because observers could not consistently differentiate between them by morphological pattern. The traditional and the modified versions were than analyzed using linear regression analysis. All approaches perform poorly when the entire sample is used. Truncation strategies to eliminate older individuals result in substantial improvement. The traditional Todd system and its modified form are found to be the best systems. When implementation is considered, a modified Todd six-phase system is recommended.

Epiphyseal union of the anterior iliac crest and the medial clavicle is examined in 605 males and 254 females in a sample of modern Americans aged 11-40 years. The sample includes American whites, American blacks, Latin-Americans, and Orientals. This is the first skeletal investigation using a large sample of individuals of known age since the McKern and Stewart study of 1957. Epiphyseal union is analyzed in terms of four stages: 1) nonunion with no epiphyses, 2) nonunion with separate epiphyses, 3) partial union, and 4) complete union. The results provide broader age ranges for the stages of union than previous studies. Age ranges for males and females are similar or vary by only 1-2 years. Racially, no major distinguishing patterns are found except for greater variability in age distributions appearing to exist among American black females. The study furnishes valuable data on epiphyseal timing in the teenage years.

A large sample (n = 370) of Central California prehistoric skeletal remains was analyzed for sexual dimorphism of long bones using nine femoral and nine humeral dimensions. Sex of all individuals was assessed using traits of the os pubis. Discriminant analysis was done separately for the robust Early Horizon sample and the Middle/Late Horizon sample. Use of multiple variables did not produce appreciably better results over the use of several of the best variables, analyzed singly. Attention is focused on measurements of maximum diameter femoral head, femoral bicondylar width, and diameter of the humeral head (transverse or vertical). These variables produce excellent separation of the sexes with about 90% accuracy for the Middle/Late Horizon sample. They have been overlooked in the recent literature in which the relative values of length versus midshaft dimensions are debated. The measurements found to be superior in this study are taken at the ends of the bones where durability of these regions is indicated by large sample sizes found in this study. We suggest workers redirect their focus from the midshaft to the ends of the long bones. The discriminant analyses presented here have greater accuracy than most claims for either long bone or cranial sex determination. These standards, based on two samples with differing robusticity, may have applicability for workers in other areas who lack large skeletal samples.