PhD Dissertations: Barbara Cage Anderson, 1987

Parturition Scarring as a Consequence of Flexible Pelvic Architecture

Adaptation for upright bipedalism and childbearing has influenced the architecture of the human pelvic girdle. Assessment of childbearing in human skeletal remains is a major concern in paleodemography and forensic anthropology. Knowledge of childbearing is also important to archaeological and anthropological analysis. This study addresses the implications of parturition stress and excessive pelvic motion during locomotion to the bony pelvis.

The bony pelvis of 226 individuals from the Hamann-Todd Collection were examined. Included in the study were 87 males, 43 Black and 44 White as well as 151 females, 74 Black and 77 White. Parity status for all females were determined from comprehensive medical records provided by autopsy and dissection.

The occurrence of scars found at attachment sites in the bony pelvis previously thought to serve as indicators of childbirth, were examined to test the hypothesis that differential fertility can be accurately determined by analysis of "scars of parturition". The results of this study show that parity is not significantly associated with pelvic pits, cavities and/or depressions. The nulliparous female may have scarring, the multiparous female may have none, and males also can exhibit pelvic scarring. Thus, the hypothesis that fertility can be determined by skeletal pelvic analysis is rejected.

The results of this study show that pelvic flexibility and sex are significantly associated with pelvic scarring. Females have a significantly greater range of motion, rotation of the sacrum and expansion of the pelvic articulations, than do males. Tightly articulated pelvic girdles show significantly less scarring than the more loosely articulated pelves. Males have tighter pelves and show less scarring than females. Relaxation or stretching of the supporting soft tissue may allow excessive movement for pelvic articulation not tightly maintained by bone. It is determined that sex and flexibility of the bony pelvis are most important in pelvic scarring and that parity is not a significant factor. This study suggest that pelvic scars at attachment sites are a consequence of excessive pelvic movement beyond the optimum during locomotion and are "scars of excess motion".