Asymmetry of the os pubis: Implications for the Suchey‐Brooks method

Abstract

Studies of skeletal development frequently document populational incidences of bilateral asymmetry. Degenerative morphological skeletal changes, attributed to age related and irregular ossification, may also progress asymmetrically, either as the result of asymmetric biomechanical factors expressed over the lifespan, asymmetric expression of physiological processes, or progressive magnification of asymmetry acquired previously during development. This study illustrates the effects of bilateral asymmetry on age at death estimates obtained from human skeletal remains. The Suchey-Brooks method, which uses the pubic symphyseal face for age estimation (Katz and Suchey, Am J Phys Anthropol 69 1986 427-435), was selected for the study based on its widespread use. Asymmetry in the Suchey-Brooks symphyseal age phases was found in over 60% of a sample composed of 20th century White male individuals from 18 to 86 years of age (N = 130). However, results suggest that the presence of asymmetry does not compromise the accuracy of the Suchey-Brooks method if the morphologically older symphyseal face of an asymmetric individual is used to estimate age at death. In addition, weak directional asymmetry and a correlation between age and asymmetry were found. This suggests that a comparison of asymmetry in this area with that in other skeletal areas, where the factors originating and influencing asymmetry are better understood, may be useful in better understanding the biological processes which underlie the age markers used in the Suchey-Brooks method.

A Study on the Asymmetry of the Human Left and Right Pubic Symphyseal Surfaces Using High‐Definition Data Capture and Computational Shape Methods

“…The results of the current study disagree with previous findings that have shown high prevalence of asymmetry for the Suchey–Brooks system as noted in over 60% of the samples analyzed . Specifically, this study does not detect either (i) the greater magnitude of asymmetry with increased age or (ii) the directional asymmetry favoring the right side .…”

“…Similar to Overbury et al., 2009 , the number of more accurate “older” estimates was compared to the number of more accurate “younger” estimates to test whether the “older” or “younger” side offered consistently better age approximation.…”

“…Schmitt's results show that calculating mean age does not offer significant improvement for the Asian sample used in the study. Overbury et al., 2009 detect weak directional asymmetry, with the right side appearing slightly older than the left. However, the authors claim that the accuracy of the Suchey–Brooks system is not affected by this directional asymmetry.…”

Using PMCT of Individuals of Known Age to Test the Suchey–Brooks Method of Aging in Victoria, Australia

“… study) found a moderate amount of asymmetry. This indicates that bilateral asymmetry in phase allocation, while not a trait observed in Western Australia, is a common feature observed in Eastern Australian individuals and in other populations of Thailand and North America . Thus, there is a continued recommendation to score pubic symphyses in isolation.…”

Preliminary Radiological Assessment of Age‐related Change in the Trabecular Structure of the HumanOs Pubis*

“…Both left and right pubes should be incorporated into further investigations, both as a source of confirmation of estimated skeletal age in light of possible asymmetry (cf. [57]) and as a check against pathological conditions that affect pelvic trabeculae and may do so asymmetrically (e.g., Paget's disease of bone). The lack of anisotropy measures in the plain film radiographic modality, where increased medio-lateral orientation of trabeculae is qualitatively apparent, should be addressed in future studies.…”