The spine is one of the most important parts of your body. It gives your body the structure, flexibility and support you need to move about freely. The spine is also designed to protect your spinal cord. The spinal cord is a column of nerves that connects your brain with the rest of your body, and allows you to control the movements of any of your body parts and your organs. This is why keeping your spine healthy is vital if you want to live an active life.

 

Your spine is made up of 24 small bones (vertebrae) that are stacked on top of each other to create the spinal column. Between each vertebra is a soft, gel-like cushion (disc) that helps absorb pressure and keeps the bones from rubbing against each other. Each vertebra is held to the others by groups of ligaments. Ligaments connect bones to bones; tendons connect muscles to bones. Therefore, tendons fasten muscles to the vertebrae. The spinal column also has joints (just like the knee or elbow) called facet joints. The facet joints link the vertebrae together and give them the flexibility to move against each other.

 

Each vertebra has a hole in the center, so when they stack on top of each other they form a hollow tube that holds and protects the spinal cord and its nerve roots. The spinal cord itself is a large collection of nerve tissue that branches off into 31 pairs of nerve roots. These roots exit the spine through spaces (neural foramina) between each vertebra and carry messages from your brain to the rest of your body to control the way you move and feel sensation.

The spine itself has three main sections: cervical, thoracic and lumbar spine. The cervical is made up of the upper seven vertebrae of the spine. The thoracic consists of 12 vertebrae in the center of the spine. The lumbar is the lower portion of the spine; it is usually made up of five vertebrae. However, some people may have six lumbar vertebrae (having six vertebrae does not seem to cause a problem).

 

A fourth section, below the lumbar spine, is the sacral region. This is actually a group of specialized vertebrae that connects the spine to the pelvis. The nerves that leave the spine in the sacral region control the bowel and bladder functions, and give sensation (feeling) to the crotch area.

A normal spine is not straight. It has three natural curves forming an S-like shape when looking at it from the side:

• An anterior (forward) curve at the neck
• A posterior (backward) curve at the ribs
• An anterior (forward) curve at the lower back

This natural curve allows for an even distribution of weight and helps a healthy spine withstand all kinds of stress. Even though the lower portion of your spine holds most of the body's weight, each segment relies upon the strength of the others to function properly.

 

Spinal Segment

 

Back specialists sometimes look at a spinal segment to understand and explain how the whole spine works.

A spinal segment is made up of two vertebrae attached together by ligaments, with a soft disc separating them. The facet joints fit between the two vertebrae, allowing for movement, and the spaces between the vertebrae allow the nerve roots to travel freely from the spinal cord to the body.

The spinal segment allows us to focus on the repeating parts of the spinal column to better understand what can be wrong with the various parts of the spine. Sometimes problems in the spine involve only one spinal segment, while other times the problems involve multiple segments.

Each spinal segment is like a well-tuned part of a machine. All of the parts should work together to allow weight bearing, movement and support. When all the parts are functioning properly, all spinal segments join to make up a remarkably strong structure called the spinal column. When one segment deteriorates to the point of instability, it can lead to problems causing pain and other difficulties.