Anatomy of the Spine

The main purpose for your spine is to support the weight of your body and to protect the spinal cord from injury. Your spinal cord also has a specific purpose; it is used to transport messages from your brain to your nerves and then the nerves to the rest of your body. Since these nerves affect all sorts of parts in the body, when the spine becomes damaged it can have a drastic effect on your daily life.

A healthy spine is a spine that is strong, flexible, and allows you to move in many different ways. Your spine is made up of many different structures that must all work together as a whole to avoid the affects of stress, strain, injury, or disease.

Curvature of the spine
A healthy spine starts out C shaped and as you begin to grow and learn to walk on two legs instead of crawl around, your spine adapts by changing its shape. As an adult the spine is naturally S shaped. In the upright position the spine is constantly being pulled forward by the weight of your body. This S curve is maintained by the muscle is your back, this is why when you have weak back muscles your posture is most often not correct and can lead to back pain.

When your spine abnormally curves forward in the lumbar area it is called Lordosis, commonly referred to as swayback. An abnormal curve in the thoracic area is termed Kyphosis or hunchback. If your spine were to curve from side to side it would be called Scoliosis.

Vertebrae
The spine consists of 33 bony vertebrae; but only 24 of these being movable. These bony parts are numbered and divided into regions. From top of your spine to the bottom you have 7 cervical (neck) numbered C1-C7, 12 thoracic (middle of your back) numbered T1-T12, 5 lumbar (lower back) numbered L1-L5, 5 sacral (base of your spine), and 4 coccygeal (base of your spine). Both sacral and coccygeal vertebrae are fused together and are unable to move.

Inter-vertebral discs
You have 23 inter-vertebral discs; a between each of the vertebrae except for L5-S1. These discs act like cushions or shock absorbers for the spine. The disc themselves are made up of a tough outer shell called the annulus fibrous, and a soft gel like center called the nucleus pulposus. As we get older these discs begin to dry out as they lose their ability to absorb water and can become brittle and flat making them less likely to absorb shock or force on the spine. This decrease in fluid is also one of the reasons why you get shorter as you age.

Facet joints
The facet joints in your spine allow it to move while keeping your vertebrae attached together. They are located on the back of your vertebrae; you have two on top and two on the bottom. The top one connects to the vertebra above it while the bottom ones connect to the vertebra below it.

Ligaments
Your ligaments are used to hold the vertebrae together, stabilize the spine and protect the inter-vertebral discs.

Muscles
The back muscles are used to stabilize the spine; there are two main groups, the extensors and flexors. Your extensors enable us to stand and lift objects and are attached to the back of your spine. Your flexors enable us to flex and bend forward. These muscles are on the front of our body and include the stomach muscles.

Spinal cord
The spinal cord is located in your spinal canal and is about 18 inches in length. The spinal cord is used to send information out to the body and brain and any damage done to it can lead to a loss in sensation or motor function below where injury occurred.

Spinal nerves
Spinal nerves are used to send information to the body and control sensation and movement. There are 31 pairs of nerves in the spine, 8 in the cervical, 12 in the thoracic, 5 in the lumbar, 5 in the sacral and 1 in the coccygeal. Each of these pairs of nerves is responsible for a certain area of the body.