Blame that bad back on your ancestors

A spine specialist trying to figure out why people so often have bad backs says he has come up with a new theory about when and how early humans evolved the ability to walk upright.

The uncannily human-looking backbone of a 21 million-year-old precursor of humans and apes gives the first clue, said Dr. Aaron Filler of the Cedars Sinai Medical Center in Los Angeles.

A major change in the vertebrae that allowed this pre-human to stand upright and carry things also made it easier to crush and strain the spongy discs between each vertebra, Filler, a medical doctor with a doctorate in anthropology proposes.

That, in turn, explains why back pain is a leading cause of disability, he said.