Extending from your neck to your hipbones, a column of 33 bones known as vertebrae is the core of your back's structure. These bones support the weight of your upper body and also house the spinal cord, which carries signals that control your movements and convey sensations. Holes in the center of each vertebra form a channel when they are stacked. The spinal cord runs through and is protected by this bony channel. Nerves extending from the spinal cord emerge through spaces between the vertebrae.