Presentation Title: “Preliminary Investigation of Age-Related Changes in Clavicular Cortical Area by Sex”
Mentor: Amanda Agnew, Anthropology
Introduction/Background:
Relationships between cortical area and age have been studied extensively in the rib and have demonstrated a negative correlation. Similar research in the clavicle is lacking with only limited studies in young cohorts that suggest a weak negative correlation between cortical area and age. Previous studies have shown that males have a larger cortical area than females in the ribs, but this relationship has not been explored in the clavicle. Additionally, clavicular cortical area parameters and their relationship with age has yet to be explored. The objective of this study is to determine whether differences exist in clavicular cortical area, total area, relative cortical area, and endosteal area across distinct age groups and between sexes.
Methods:
Histological sections were obtained from the left clavicles of 31 post-mortem human subjects (females = 15, males = 16; Age range= 23-98, SD = 23) and were age-matched across decades, except for the third decade. Sections were taken from each clavicle at the midshaft site and prepared following standard hard tissue histology procedures. All slides were imaged at 40x magnification. Cross-sectional areas, specifically cortical area, total area, and endosteal area, were collected via semi-automated methods (1) using ImageJ software (2). Relative cortical area was calculated (Ct.Ar/Tt.Ar) to normalize the data.
Results:
Linear regression tests were conducted to examine the strength of the relationships. Of the four relationships investigated in each sex, only the endosteal area of males was statistically significant. However, the overall trends demonstrated that cortical area and relative cortical area increased with age in both males and females, whereas endosteal area decreased with age in both males and females. Total area remained the same throughout life in both sexes.
Conclusions:
These trends suggest that clavicles infill with age rather than undergo cortical thinning as observed in ribs. Future work will expand the sample and independent variables in order to better understand how the clavicle is changing throughout life.
References:
1. Dominguez VM, Agnew AM. The use of ROI overlays and a semi-automated method for measuring cortical area in ImageJ for histological analysis. Am J Phys Anthropol. 2019 Feb;168(2):378-82. doi: 10.1002/ajpa.23747
2. Rasband WS. ImageJ. Bethesda, Maryland, USA: U.S. National Institutes of Health, 1997–2016.