The spine curves gently in an S shape that helps absorb shock while walking.

The longer version

Curves in the spine are not a flaw but a design that turns a rigid column into a springy one. Viewed from the side, the neck and lower back bend one way while the upper back and pelvis region bend the other, giving the gentle double curve.

This shape spreads the jolt of each footstep instead of passing it straight up to the skull. The bones themselves stack in segments separated by discs of tough cartilage, which compress slightly and rebound. Ligaments and the muscles along the column add tension, so the whole structure absorbs and returns energy with every stride.

Where this entry sits

These facts look at how the human body works in ordinary moments, from breathing and blinking to balance and sleep. They focus on anatomy, senses, and small reactions that happen constantly without any conscious effort. The full list sits on the Human Body page, where every entry is listed in order.