The effects of alcohol and drug abuse on the sternal end of the fourth rib

Abstract

Estimation of skeletal age at death is based on the premise that osseous tissue undergoes predictable and patterned changes through the life of the individual that can be quantified and accurately correlated with skeletal age. The utility of any method of estimating skeletal age at death is dependent on two basic principles. First, the descriptive parameters of the method must account for the range of phenotypic variation observed at the skeletal site. Second, the method must be accurate when applied to an unknown individual, regardless of the individual's unique life history. This study examines the reliability and accuracy of the sternal end of the fourth rib method for the determination of skeletal age at death and explores whether chronic substance abuse alters the pattern of change at the sternal end of the fourth rib. Additional variables considered include gender, race and the presence of thoracic disease. One hundred and fifty five sets of ribs, obtained during forensic autopsy, are examined and age at death determined in two separate trials. All antemortem data, with the exception of gender, are collected following completion of rib examination in order to prevent biasing the observer. Reliability (intra-observer error) and accuracy are computed utilizing the kappa statistic. The results suggest that the sternal end of the fourth rib is a reliable but not an accurate method of determining skeletal age at death. The variables of sex, race, and thoracic disease all influence the accuracy of the method. Chronic substance abuse appears to influence both the reliability and the accuracy of the method.