BEFORE WE CAN talk about spinal disorders and potential surgeries to treat these disorders, it will be helpful to take a quick look at the spine. If you are already familiar with the structure and function of the spine, feel free to skip ahead to the next section.
These intervertebral discs are wonderful structures that allow the spine to move in wonderful ways. These discs also help protect the vertebrae from each other, keeping them from wearing against each other. And because of the stresses and motion that these discs must endure for a lifetime, they often get injured as well. The human spine gives strength and form to our bodies and is responsible for our ability to stand and walk with an upright posture. It is divided into three sections: cervical, thoracic and lumbar. The spine consists of 24 vertebrae that are connected to one another by intervertebral discs (we will just call them “discs” from this point), facet joints (joints formed from protrusions on the vertebrae) and the various ligaments; together they form a strong but flexible structure. The cervical and lumbar spine are exceptionally mobile. The thoracic spine in conjunction with the ribs forms an almost completely rigid “cage” to ensure the function of the lungs, heart and other organs. In addition to providing strength and structure to the core of the human body, the spine also protects the spinal cord, which runs through the spinal column.
The spine and its components form the major “axis organ” of the body, and all other organs depend on the spine in one way or another. Likewise, the spine can only perform its function with an intact muscular system.
To understand the disc, you need to first understand the vertebrae. The vertebrae are the bones in your spine. They are what gives strength and structure to your body. Each of the 24 vertebrae in a spine are unique. Though no two are quite the same, they do share common structures and function.
The vertebrae in the thoracic spine allow very limited mobility. Instead, with the ribs, they provide a mostly rigid upper core that supports and protects your lungs, heart, and other critical organs. Because of this relatively rigid structure, the thoracic vertebrae tend to bear stresses together, with very limited force borne by an individual vertebra. As such, we see far fewer thoracic spine injuries and degeneration than we do in other areas of the spine.
The cervical and lumbar spine are another story. The vertebrae in a healthy cervical spine and lumbar spine allow significant motion. Barring injury, their form allows you to bend down and touch your toes, and to bend your neck to put your chin on your chest. As you may have experienced if you have back problems yourself, any compromise in motion in these areas can result in serious limitations and pain. The high level of mobility in the lumbar and cervical spine comes at a cost; these areas are far more prone to injury and degeneration than the thoracic spine. The relative freedom of movement means a single lumbar or cervical vertebra can be subjected to much greater stress than a thoracic vertebra. The additional movement also causes these areas of the spine to wear out at an earlier age as a result of degenerative processes. For this reason, lumbar and cervical spine injuries are very common. Unfortunately, because the spinal column also surrounds and protects the spinal cord from injury, changes to the segments of the spine can also impact the spinal nerves structures and cause excruciating pain and other symptoms.
In between the vertebrae are soft, flexible discs that serve to separate the vertebrae and allow them to move in relation to each other. These are called intervertebral discs for the simple reason that they sit between the vertebrae. For simplicity, they are often referred to merely as discs.
The exterior of each disc is composed of a fibrous material called the annulus fibrosis. This surrounds and protects the soft fluid-filled center, the nucleus pulposus. While the names of these structures are not important, their function is very important. You see, this combination of a soft center and a strong but flexible exterior allows the spine to move in six distinct ways.
Learn More about the wonderful new Disc Replacement Implants that allows the spine to move in all six distinct ways!