I hear this many times each week: “Doc – it’s my sciatica again!” The term ‘sciatica’ often gets used improperly to describe all kinds of back pain and/or pain/numbness/tingling in the legs. There are several different causes of back pain, numbness or tingling, so let’s take a moment and do a quick review to understand two of the most common causes.
Each sciatic nerve (you have 2), starts when several nerve branches from your lower lumbar vertebrae and sacrum join together inside your pelvis. The nerves then travel down the back of each of your thighs, lower legs and all the way to your toes. As the sciatic nerve divides into smaller nerve branches, it delivers nerve signals to and from the muscles and skin. When lower back subluxations irritate nerves, poor movement, inflammation & associated tightening of soft tissue (muscle spasm) can cause shooting pain, weakness, numbness or tingling that often occurs along the branches of the sciatic nerve.
For those with lower back degeneration or bone spurs, it is more likely that those jagged edges of bone will irritate the nerves and cause pain. If disc damage has occurred, the nerve irritation can cause the same pain signals. It’s important to note also that 20-40% of people have disc herniation without any pain! Less than 10% of our nerves have the ability to sense pain.
Sacroiliitis (say – kroe – ill – e – i – tis)
This occurs when poor joint mechanics in the back of the pelvis cause inflammation leading to nerve irritation. Your spine sits on your sacrum which acts like a keystone in your pelvis. The sacrum creates a joint on each side of it with the ilium bones. These joints are called the sacroiliac (SI) joints. Common causes of sacroiliitis are falls, poor sleeping positions, too much sitting and difference in leg length. The SI joints also significantly increase in their mobility during pregnancy and are more easily irritated. They gain movement but sacrifice stability. These joints must work properly as they support the entire spine.