Anatomy and Sources of Back Pain
The spine can be thought of as containing the following components, each of which can be a source of pain.
Discs (Intervertebral Discs)
Discs are made up of the:
- Nucleus – This structure serves as a load bearing cushion
- Annulus — A network of circularly arranged fibers that provide structural support
The nerve and blood supply of the discs come from adjacent edges of vertebral bone (end-plates) and the outer layers of the annulus. Disc pain can occur when small, inner tears of the annulus reach these nerve fibers, also called discogenic pain, or with “microfractures” of the end-plates, also called vertebrogenic pain.
These painful conditions can occur due to trauma. They can also be caused by degenerative changes. Disc degeneration and herniation are also heavily influenced by genetics. Keep in mind that visible imaging (MRI) findings aren’t always associated with pain. In addition, your pain can often be significantly reduced or even eliminated with proper treatment.
Disc herniations associated with a tear in the annulus can cause both back pain and the pain of pinched or inflamed nerves. Disc herniations fall into three different categories:
- Protrusion
- Extrusion
- Sequestration (free disc fragment)
These disc protrusions cause pain in the nerve root, also known as sciatica/radiculitis, by compressing the nerve root or causing inflammation. Fortunately, disc protrusions resorb in many cases. In addition, treatment can significantly reduce pain and restore the ability to function by reducing nerve inflammation as the condition resolves. Surgery may be required if:
- The pain of a pinched nerve doesn’t improve
- You experience significant weakness
- The situation becomes worse
The Denver Spine & Pain Institute works closely with the best surgeons in the area, and we can counsel you regarding indications for surgery to make your decision an informed one. We can also provide you with post-operative care and rehabilitation.
Facet Joints (Zygapophysial Joints)
There are two facet joints at each level of the spine. They work with the disc to create a weight bearing “tripod.” The facet joints allow spinal motion. They can be injured from a twisting motion or due to trauma. In many instances, the onset of pain can occur gradually.
The disc is responsible for supporting most of your weight. However, as the discs degenerate and become thin, more of your weight load shifts to the facet joints. This can cause degeneration in the joints, which may result in pain.
Sacroiliac Joints (SIJ)
The sacroiliac joints (SIJs) are complex, boomerang shaped joints that are supported by strong ligaments and muscles. There is normally slight torsional motion at the joints while walking and moving. The joint surfaces can, however, shift out of position or become locked. This can cause pain, and the surrounding muscles can become dysfunctional.
Some muscles will become tight and painful, while others stop doing their job in order to maintain normal stability and movement of the SIJ. This is why sacroiliac joint problems often cause piriformis muscle problems.