Ouch, I have Sciatica; what is that really?

Many of my patients have told me, “I have Sciatica”, but the distribution of pain or pain-like (numbness, tingling, itching, warmth, or burning) sensation that each describes are many times different and sometimes very different. Wouldn’t one think the symptoms would be the same or at least similar for everyone with that condition? Some patients are not even really sure what sciatica means. So what is sciatica? When you get that diagnosis what does that mean and how do you get rid of it?

Sciatica is referred pain and it is called sciatica because many times the pattern of the referred pain just happens to be down the back of the leg, which is the same distribution as the sciatic nerve. Sometimes people will come in and say they have sciatica with pain only in the buttock and sometimes people even come in with pain in the side and/or front of the leg and say they have sciatica. So what is going on?

Well, the pain or pain-like sensation a persons feels may not necessarily be from compression of the sciatic nerve. Actually, more likely it is “higher up” at the inter-vertebral foramen. The intervertebral foramen is the structure or “hole” where the spinal nerves exit the bone structure of the vertebrae. The actual spinal cord is inside the vertebrae and in order for the nerves to reach the rest of the body; the nerves have to exit through this small “hole” that is formed from the top and bottom of each vertebra. This “hole” just also happens to be right at the junction of the intervertebral disc as well. So, sometimes even a small bulge or herniation of the disc can pinch or compress the nerve root there at the intervertebral foramen. The Figure 1 and Figure 2 below show the intervertebral foramen and the spinal cord within the vertebrae.

          

Furthermore, the sciatic nerve is not even formed until portions of the nerve roots from L4 to S3 vertebral levels link up at sciatic notch in the pelvis. The sciatic nerve is formed outside of the “spinal area” from portions of the L4 to S3 nerve roots at the sacral plexus. The sacral plexus is actually located in the pelvic area and sits just above the pirifomris muscle. The sciatic nerve emerges from the sacral plexus and passes beneath the piriformis and through the sciatic notch, exiting the pelvis. See the figures 3 and 4 below.

It does get confusing, but basically the sciatic nerve gets a lot of credit for the referred pain in the leg. Many times the actual culprit is an inflamed disc(s) or ligament(s) pinching the nerve root at the intervertebral foramen and referring pain down the leg. However, we all call it sciatica because that’s the name of the big nerve in the back of the leg.

To clarify, there are many documented pain patterns that show us what vertebral level of injury causes what referred leg pain pattern. The difference in these pain patterns is that they originated as empirical in nature and have been passed on from more experienced therapists through the years. That lead to research and confirmation and now this data has become more and more documented in textbooks and articles. See Figure 5 below for the pain patterns of L3 through S1 vertebral levels.

So why make the distinction that the “pinch point”, if you will, occurs before the sciatic nerve is even formed? Well if we know more specifically what vertebral level is at fault for your “sciatic pain”, then we can be more accurate in our treatment. In summary, the term Sciatica is more accurately a description of your pain, rather than a diagnosis.  To really know what is going on, you should find an experienced therapist who has knowledge of referred leg pain patterns and can determine if the sciatic pain your experiencing is from entrapment of the nerve root at the intervertebral foramen or a more peripheral structure, which is actually a much more rare situation.