Everyone’s spinal column is comprised of 33 bones called vertebrae. Through the middle of each vertebra is a cavity, and together these cavities form a tunnel through which the spinal cord passes. In essence a massive collection of nerve fibers, the spinal cord serves as the communication channel between the brain and the rest of the body.
The nerve fibers that branch out from this central highway are called peripheral nerves, and the nerve impulses that travel throughout the nervous system are what directs the body’s movements and what receives sensations from the outside world for the brain to process.
One of the principal functions of the spinal column is to protect the spinal cord. Protecting the spinal cord is essential, because damage or pressure on the nerves here (or in other parts of the body) can cause pain.
Other symptoms may include numbness, tingling, burning, pressure, or weakness. Severe damage to the spinal cord may cause paralysis below the site of injury.
As an essential part of the skeleton, the spinal column also serves to support the weight of the body. Each vertebra varies in size depending its role in supporting body weight.
Functional spinal units are the elementary components of the spinal column. Each unit consists of two vertebrae and a cartilaginous disc in between them. Serving as cushions between the vertebrae, these discs are made of tough fibrous tissues called annulus fibrosis and have a gelatinous substance called the nucleus pulposus in the center. In healthy discs , the fibrous tissues fully enclose the nucleus pulposus. This arrangement is what allows the spine to support seated postures. Meanwhile, standing postures are aided by two specialized joints on the back of each functional spinal unit, and they also protect the spinal cord from damaging movements. Fibrous ligaments connect these joints, helping to stabilize the spinal column.
Doctors divide the spine into four sections: the cervical, the thoracic, the lumbar, and the sacral. Each of the 33 vertebra is assigned a letter and number depending on where it is located in the spine.