Fossil Men
Kermit Pattison

In human evolution, spine was a place of radical transformation. At some point, our trunk redeployed from horizontal to vertical and assumed a form unique in the animal kingdom—the S-shaped lordotic spine.

This recurved spine centers our weight over the hips and feet, so standing requires only slightly more energy than sitting. The lordotic spine is the sine qua non of bipedality, and without it we could not manage our strange manner of walking and running.

This makeover came with severe costs. Standing erect required anatomical compromises that rendered the human spine vulnerable to compressed nerves, slipped discs, osteoarthritis, strained muscles and ligaments, sacroiliac joint dysfunction, and more.

Such troubles are old news: even fossil skeletons are rife with spinal pathologies.