Spine

The spine is the column of bones that runs down the middle of your back. It is also called the backbone or the vertebral column. The spine holds your body up, lets you bend and twist, and protects one of the most important parts of your nervous system. Almost every animal with a backbone, from a goldfish to a giraffe, has a spine that does these same jobs.

Your spine is not one solid bone. It is a stack of 33 small bones called vertebrae. Between most of the vertebrae are soft pads called disks. The disks act like little cushions. They keep the bones from grinding against each other when you jump, run, or carry a heavy backpack.

The spine has four main sections. The top seven vertebrae are in your neck. Below those are 12 vertebrae in your upper back, where your ribs attach. Then come five larger vertebrae in your lower back, where most of your weight rests. At the bottom are nine vertebrae that are fused together into two solid pieces, the sacrum and the tailbone. The tailbone is left over from a tail that humans had millions of years ago.

If you look at a spine from the side, it is not straight. It curves gently in an S-shape. These curves act like springs and help your body absorb shocks when you walk or land from a jump.

Inside the stack of vertebrae is a hollow tunnel. Running through that tunnel is the spinal cord, a thick bundle of nerves about as wide as your finger. The spinal cord carries messages between your brain and the rest of your body. When you decide to wiggle your toes, the message travels from your brain down the spinal cord and out to your foot in less than a second. The bones of the spine wrap around the spinal cord like armor.

Because the spinal cord is so important, doctors take spine injuries very seriously. If the cord is badly hurt, the messages cannot get through, and parts of the body below the injury may not be able to move or feel. Scientists are still working on ways to repair damaged spinal cords, and it is one of the biggest open challenges in medicine.

You can take care of your spine by sitting up tall, lifting heavy things with your legs instead of your back, and moving your body often.