The Spinal Column

The spinal column consists of 24 separate bones called vertebrae, plus the fused bones of the sacrum and the coccyx (Fig. 1). Your spinal column is the central support for the upper body, carrying most of the weight of your head, chest, and arms. Together with the muscles and ligaments of your back, your spinal column enables you to walk upright.

Vertebrae and Discs

The Lumbar Vertebrae

The vertebrae in the lumbar (or lower back) portion of your spine are under constant pressure from the weight of your upper body, even when you are simply sitting in a chair. The "wear and tear" of this pressure is what usually leads to problems associated with the lower back.

The Intervertebral Discs

The intervertebral discs (Fig. 1, above) are composed of a fiber-like outer lining (the annulus) and a gelatin-like inner core (the nucleus ) (Fig. 2). These discs act as the spine's "shock absorbers," preventing vertebra from rubbing against one another and providing much of the flexibility found in your spine. Because they are constantly being "squeezed" under the pressure of the spinal column, it is the intervertebral discs which first show signs of the "wear and tear" associated with the aging process.

The Spinal Nerves

Running through the center of the spinal column is the spinal cord, which ends in the lumbar spine in a bundle of nerves called the cauda equina (Fig. 2, above). At each disc level, a pair of spinal nerve roots branch off from the spinal cord or cauda equina and pass through an opening called the foramen (Figs. 2 & 3). Young, "plump" discs help to keep this opening wide enough for the spinal nerve roots to pass through freely.

The Growth of Bone Spurs

As your spine ages, the gelatin-like centers of your discs begin to dry out, thereby reducing their effectiveness as "shock absorbers." As this protection is lost, the simple "wear and tear" of everyday activity can cause the bone matter of your vertebrae to develop jagged edges, called bone spurs. As these spurs develop and extend outward, they can cause both the spinal canal and the foramen to become narrowed (Fig 4). The result is often the pinching (compression ) of the cauda equina and/or a spinal nerve root.

The "Slowly Closing Window"

As discs "dry out," your vertebrae begin to "settle" (Fig. 3, above ). This "settling" causes the window-like openings of the foramen and the spinal canal to become smaller and smaller (Figs. 3 & 4, above). Eventually, these openings can become so small that a spinal nerve(s) becomes "pinched" against a vertebra. It's similar to slowly closing a window on your hand. There will be a point at which you begin to feel the pressure. The more the window is closed, the greater the pressure - and the greater the pain.

Symptoms

When a spinal nerve is pinched by a narrowing of the foramen (lateral recess stenosis), the symptoms can include intense pain, numbness and/or weakness in one leg. When the cauda equina is compressed by a narrowing of the spinal canal (lumbar canal stenosis ), the pain, numbness and/or weakness appears in both legs.

The Aging Spine

The Body's Aging Process

As we get older, our bodies go through many changes. We all recognize that we will not see or hear as well as we once did. This is a natural process. We either accept these changes or we make adjustments to compensate for them, such as getting glasses or a hearing aid.

The Aging Spine

Your spine is no different than any other part of your body. As it ages, it goes through natural changes. In a condition often referred to as the Aging Spine (or degenerative disc disease), the gelatin-like centers of your discs begin to dry out, causing them to become compressed or flattened. This, in turn, causes your vertebrae to "settle." It's one reason most people actually become shorter as they get older.

Individual Differences

If the aging of the spine is a natural process and happens to everyone, why might you end up with back problems while your neighbor is seemingly unaffected? The answer is quite simple: everyone's spine is unique. Genetic make-up of the spine is the most important factor, but body weight, posture and your level of physical activity also helps determine if you will be adversely affected by the aging process.

Compressed Spinal Nerves

In the rest of this website, you will see what happens to the spine as it ages. You will see that the end result for many people is a "pinching" of the central bundle of nerves (the cauda equina ) or a spinal nerve root(s). The aging of the lumbar spine is known as lumbar canal stenosis and can lead to cauda equina compression and/or lumbar radiculopathy (compression of a spinal nerve root).

Treatment Options

Since the aging of the spine is a natural and irreversible process, treatment options are limited to relieving your symptoms (numbness, pain, etc.) and to removing pressure on the spinal nerves. Treatment options include:

1. Taking Medication: For some, medication may help to ease the pain in the affected area and thereby provide relief.
2. Using Physical Therapy: Gentle exercise and physical therapy may be recommended to help build up muscles which support the spinal column and thereby assist in relieving some symptoms.
3. Having Surgery: For those with severe compression of the cauda equina and/or spinal nerves, surgery is recommended to relieve pressure on the spinal nerve(s).

Before you decide on any form of treatment, be sure you understand the risks and benefits involved with each option.

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