by Kirstin Weible, PT, ScD, COMT
What’s with my disc?
Between each vertebra lies an intervertebral disc. It is made of many layers of outer tissue similar to what a ligament is made of, called the annulus fibrosus, and a softer gel-like center, called the nucleus pulposus. Behind the disc is a space called the intervertebral foramen (“foramen” means “hole” or “space”). In a healthy spine, this space is nice and open. The intervertebral foramen is where the spinal nerves exit the spinal cord to travel to every other part of the body. The functions of these nerves are to provide motor control (movement) of muscles and sensation (pressure, temperature, tickle, tingle, etc.) for our perception.
Over the course of time, it is normal for our discs to experience changes in structure, shape, and overall integrity for many reasons including continued repetitive performance of certain jobs tasks, acute injuries, poor trunk control, and general use of our spine. Nearly everything we do involves movement of the spine in some capacity. These changes are normal and do not indicate something is “wrong” or “needs fixed”. Rather, it just means you’ve lived life right! These changes can, and do in roughly half of the population, create some level of pain in the spine. Various imaging techniques can help to describe these changes. For instance, an x-ray does not show soft tissue structures such as discs, but it can show that the vertebrae are closer together at some levels than others indicating that a disc has lost height and integrity. An MRI, however, does show discs and can be quite useful in illustrating these normal changes. An MRI is inherently just a picture, however, and cannot be used to diagnose what your problem is unless it correlates with your specific symptoms. Physical therapists are experts in matching the two to provide differential diagnosis! The following illustrates what the various words on an imaging report mean.
In cases of a bulged disc, pain is often localized to the low back and can occasionally refer into the buttock. Pain can be the size of a thumbprint or more diffuse such as a palmprint. These differences do not indicate a difference in severity, only a difference in the affected structures. In the case of a thinning, bulged, or herniated disc, the space of the intervertebral foramen begins to narrow (“stenosis” means “narrowing”), thereby shrinking the space where the nerve roots emerge. The following image illustrates how a herniated disc can begin to infringe on a nerve root.
In the case of a nerve root-related pain, as illustrated above, a person will begin to experience pain and dysfunction in the buttock, thigh, lower leg, or foot. This can feel like shooting pain, numbness, burning, or tingling. The location and severity of these symptoms varies widely depending on a number of factors including which disc/nerve is involved and to what capacity and other nearby structures.
The research shows that nearly ALL people aged 70 years and older have discs that start to look thinner, sometimes referred to as “degenerative.” These changes certainly begin at a younger age in many folks, especially those with a history of acute injury or trauma, chronic pain, or overuse. So if you have a disc issue, while your pain is unique and requires an individualized treatment plan, you are in good company with your fellow humans, and we at The Motive Physical Therapy Specialists have lots of experience in treating your condition! Our approaches work to improve the muscular strength and stability or your core and hips to help support your ailing disc(s) as well as to centralize your symptoms. Centralization is what we call it when your symptoms travel less distance down your leg. For example, if you were having symptoms in your foot, and now they are only going as far as your thigh, you are improving! If you know or suspect you have back or leg pain related to a disc problem, please contact us with questions or schedule an evaluation!