Sciatica is the common term used for pain down the leg stemming from irritation to the sciatic nerve, in the back. It is often part of a condition that health professionals call “lumbar radiculopathy”.
The sciatic nerve is the largest nerve in the body. It starts as five “nerve roots” in lower back spinal cord. Outside the spine these nerve roots join and form the sciatic nerve, running deep through the muscles of the hip and bottom, then down the back of the leg, before it divides again into smaller nerves behind the knee, and in the foot.
Sciatica is a nerve pain caused by irritation of or pressure on the sciatic nerve itself. It should be said, however, that pain down the leg can also come from a number of other causes.
The sciatic nerves (one for each leg) carry all sorts of signals from the brain to the lower limbs, and from the lower limbs back to the brain.
Some of these signals control muscles (motor nerves). Some sense movement of joints (proprioceptive nerves). Some sense pain or temperature changes (nociceptors). Sudomotor nerves, control the sweat glands.
When we get sciatica, it is likely because something is irritating the sensory parts of the nerve.
That irritation to the nerve might feel like pain, pins and needles, numbness or even like insect crawling on the leg.
If the sensory part of the nerve is affected, then the motor nerve might also be affected. If the motor (muscle controlling) nerve is affected, it would show up as weakness of certain muscles.
Aggravated discs pressing on sciatic nerves are not the only cause of sciatica. There are many other causes, several of which are listed, below:
- Sacroiliac pain: Your pelvis can produce pain similar to that of a sciatic pain. The difference is that the leg pain is “referring” from the joint and not from nerve irritation. Typically these do not radiate beyond the knee.
- Facet joint pain from the lumbar spine. These are the little “knuckle” joints in the spine. Typically, facet joint pain does not travel past the knee.
- Stenosis: Narrowing of the spinal canal or the space where the nerve exits the spine can occur with arthritis and other conditions. It becomes more common in old age.
- Spondylolisthesis: This is a reasonably common condition, in which one vertebrae slips forward over another one due to a stress fracture or fractures acquired in childhood. Most people with this condition do not know that they have it. It sometimes causes sciatica. The Chiropractor will easily be able to diagnose this condition with an x-ray, if they suspect it.
- “Muscle knots”: Traditionally tight, sensitive band of muscle has been called trigger points. Certain muscles will produce pain down the leg similar to that of the sciatic nerve. Some common sites are gluteus maximus, gluteus minimus and the piriformis muscle.
- “Piriformis Syndrome”: Commonly the sciatic nerve can be trapped under the piriformis muscle, deep in the hip and produce leg symptoms. This one is easy to spot, and very easy to treat.
- Systemic disorders: diabetes, thyroid disorders, alcoholism, malnutrition, cancer, infections.
If you are experiencing symptoms listed above, a visit to Afferentation Chiropractic will enable you to receive a thorough assessment and diagnosis to see how we may be able to assist and relieve your symptoms.