Learning About Your Lower Back

When it is healthy, the low back allows you to bend and stretch without pain. But if your low back problem pinches a nerve, you may have pain, tingling, or numbness all the way down your leg. Sometimes merely standing or sitting causes symptoms.

A Healthy Spinal Column

The spinal column is a stack of bones (vertebrae) that are separated by soft pads of tissue (disks). Each of these bones has a canal that runs top to bottom. Together these canals form a tunnel called the spinal canal. Running through this canal are nerves. These nerves carry signals between the brain and body. When a spinal column is healthy, the following parts fit together without pressing on the nerves:

• Vertebrae are the bones that make up the spine.
• The lamina of each vertebra forms the back of the spinal canal.
• A foramen is a small opening. This is where a nerve leaves the spinal canal.
• Disks serve as cushions between vertebrae. A disk's soft center absorbs shock during movement. This allows each vertebra to rock back and forth and side to side, so the body can move freely.

When a Back Problem Pinches a Nerve

The symptoms in your back or leg may be due to pressure on a nerve. This pressure may be caused by a damaged disk or by abnormal bone growth. Either way, you may feel pain, burning, tingling, or numbness. If you have pressure on a nerve that connects to the sciatic nerve, pain may shoot down your leg.

Pressure from the Disk

Constant wear and tear can weaken a disk over time. The disk can then be damaged by a sudden movement or injury. If its soft center begins to bulge, the disk may press on a nerve. Or the outside of the disk may tear, and the soft center may squeeze through and pinch a nerve.

Pressure from Bone

As a disk wears out, the vertebrae right above and below the disk begin to touch. This can put pressure on a nerve. Often abnormal bone (called bone spurs) grows where the vertebrae rub against each other. This can cause the foramen or the spinal canal to narrow (called stenosis) and press against a nerve.

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