1Skeletal Biology Research Laboratory, Division of Anatomy, The Ohio State University, 2Department of Anthropology, The Ohio State University
March 27, 2015 , Archview Ballroom
Secondary osteons are often assessed in histomorphometric analyses, but the forces acting on osteon size are as yet poorly understood. This study examines the relationships of sex, age, cortical area, and cortical porosity on osteon area in the ribs, also exploring differences between the pleural and cutaneous cortices. The sample consisted of 49 mid-shaft 6th ribs, from individuals 6–92 years of age. Tested variables included percent absolute cortical area (%Ct.Ar), percent cortical porosity (%Po.Ar), and average osteon area (On.Ar), which were collected or calculated for each of the cutaneous and pleural cortices and then pooled for the total rib for each individual.
A t-test revealed no significant differences between sexes; samples were pooled for all further analyses. Significant correlations were found between age and both %Ct.Ar and %Po.Ar. As such, multiple linear regression tested the effect of %Ct.Ar and %Po.Ar on On.Ar, with age treated as a covariate. Results indicated that %Ct.Ar is the only variable in complete ribs to have a significant relationship with On.Ar (p=0.024). On the cutaneous cortex, both %Ct.Ar and age (p=0.014 and p=-0.025, respectively) were significant, while on the pleural cortex, On.Ar was found to have no significant relationship with any of the variables.
These results suggest that the amount of cortical area available for remodeling influences the size of osteons. While %Po.Ar was not statistically significant, trends indicate that as intracortical porosity increases, On.Ar decreases, further supporting this suggestion. Differences between the cortices are attributed to their known differential rates of bone loss.