Synopsis:
The human pelvis provides a unique solution to the dual constraints of bipedality and birth.
This lecture reviews the distinctive shape of the human pelvis and its role in bipedal locomotion. In living people, the pelvis is the most informative skeletal indicator of whether bones represent male or female individuals. The reasons for this stem from the dual constraints operating on our pelvis -- the need to maintain effective bipedal stance and locomotion, and the need to birth infants through the birth canal.
The lecture discusses the differences between humans and australopithecine pelvic anatomy, using Lucy as the prime example. It includes some discussion of the pelvis of Ardipithecus as well as the pelvis of Homo erectus and Neandertals.
Study questions:
- Why do apes have a pelvic form that tends to "capture" their lower lumbar vertebrae, stiffening their lower backs?
- Has the human pelvic inlet reached its maximum possible size, or could we evolve to give birth to larger infants?