What is sciatica?
Sciatica is nerve pain from an injury or irritation to the sciatic nerve, which originates in your buttock/gluteal area. The sciatic nerve is the longest and thickest (almost finger-width) nerve in the body. It’s actually made up of five nerve roots: two from the lower back region called the lumbar spine and three from the final section of the spine called the sacrum. The five nerve roots come together to form a right and left sciatic nerve. On each side of your body, one sciatic nerve runs through your hips, buttocks and down a leg, ending just below the knee. The sciatic nerve then branches into other nerves, which continue down your leg and into your foot and toes.
True injury to the sciatic nerve “sciatica” is actually rare, but the term “sciatica” is commonly used to describe any pain that originates in the lower back and radiates down the leg. What this pain shares in common is an injury to a nerve -- an irritation, inflammation, pinching or compression of a nerve in your lower back.
If you have “sciatica," you experience mild to severe pain anywhere along the path of the sciatic nerve – that is, anywhere from the lower back, through the hips, buttocks and/or down your legs. It can also cause muscle weakness in your leg and foot, numbness in your leg, and an unpleasant tingling pins-and-needles sensation in your leg, foot and toes.
What does sciatica pain feel like?
People describe sciatica pain in different ways, depending on its cause. Some people describe the pain as sharp, shooting, or jolts of pain. Others describe this pain as “burning,” "electric” or “stabbing.”
The pain may be constant or may come and go. Also, the pain is usually more severe in your leg compared to your lower back. The pain may feel worse if you sit or stand for long periods of time, when you stand up and when your twist your upper body. A forced and sudden body movement, like a cough or sneeze, can also make the pain worse.
Can sciatica occur down both legs?
Sciatica usually affects only one leg at a time. However, it’s possible for sciatica to occur in both legs. It’s simply a matter of where the nerve is being pinched along the spinal column.
Does sciatica occur suddenly or does it take time to develop?
Sciatica can come on suddenly or gradually. It depends on the cause. A disk herniation can cause sudden pain. Arthritis in the spine develops slowly over time.
How common is sciatica?
Sciatica is a very common complaint. About 40% of people in the U.S. experience sciatica sometime during their life. Back pain is the third most common reason people visit their healthcare provider.
What are the risk factors for sciatica?
You are at greater risk of sciatica if you:
- Have an injury/previous injury: An injury to your lower back or spine puts you at greater risk for sciatica.
- Live life: With normal aging comes a natural wearing down of bone tissue and disks in your spine. Normal aging can put your nerves at risk of being injured or pinched by the changes and shifts in bone, disks and ligaments.
- Are overweight: Your spine is like a vertical crane. Your muscles are the counterweights. The weight you carry in the front of your body is what your spine (crane) has to lift. The more weight you have, the more your back muscles (counterweights) have to work. This can lead to back strains, pains and other back issues.
- Lack a strong core: Your “core” are the muscles of your back and abdomen. The stronger your core, the more support you’ll have for your lower back. Unlike your chest area, where your rib cage provides support, the only support for your lower back is your muscles.
- Have an active, physical job: Jobs that require heavy lifting may increase your risk of low back problems and use of your back, or jobs with prolonged sitting may increase your risk of low back problems.
- Lack proper posture in the weight room: Even if you are physically fit and active, you can still be prone to sciatica if you don’t follow proper body form during weight lifting or other strength training exercises.
- Have diabetes: Diabetes increases your chance of nerve damage, which increases your chance of sciatica.
- Have osteoarthritis: Osteoarthritis can cause damage to your spine and put nerves at risk of injury.
- Lead an inactive lifestyle: Sitting for long period of time and not exercising and keeping your muscles moving, flexible and toned can increase your risk of sciatica.
- Smoke: The nicotine in tobacco can damage spinal tissue, weaken bones, and speed the wearing down of vertebral disks.
Is the weight of pregnancy the reason why so many pregnant women get sciatica?
It’s true that sciatica is common in pregnancy but increased weight is not the main reason why pregnant women get sciatica. A better explanation is that certain hormones of pregnancy cause a loosening of their ligaments. Ligaments hold the vertebrae together, protect the disks and keep the spine stable. Loosened ligaments can cause the spine to become unstable and might cause disks to slip, which leads to nerves being pinched and the development of sciatica. The baby’s weight and position can also add pressure to the nerve.
The good news is there are ways to ease sciatic pain during pregnancy, and the pain goes away after birth. Physical therapy and massage therapy, warm showers, heat, medications and other measures can help. If you are pregnant, be sure to follow good posture techniques during pregnancy to also ease your pain.
What causes sciatica?
Sciatica can be caused by several different medical conditions including:
- A herniated or slipped disk that causes pressure on a nerve root. This is the most common cause of sciatica. About 1% to 5% of all people in the U.S. will have a slipped disk at one point in their lives. Disks are the cushioning pads between each vertebrae of the spine. Pressure from vertebrae can cause the gel-like center of a disk to bulge (herniate) through a weakness in its outer wall. When a herniated disk happens to a vertebrae in your lower back, it can press on the sciatic nerve.
- Degenerative disk disease is the natural wear down of the disks between vertebrae of the spine. The wearing down of the disks shortens their height and leads to the nerve passageways becoming narrower (spinal stenosis). Spinal stenosis can pinch the sciatic nerve roots as they leave the spine.
- Spinal stenosis is the abnormal narrowing of the spinal canal. This narrowing reduces the available space for the spinal cord and nerves.
- Spondylolisthesis is a slippage of one vertebra so that it is out of line with the one above it, narrowing the opening through which the nerve exits. The extended spinal bone can pinch the sciatic nerve.
- Osteoarthritis. Bone spurs (jagged edges of bone) can form in aging spines and compress lower back nerves.
- Trauma injury to the lumbar spine or sciatic nerve.
- Tumors in the lumbar spinal canal that compress the sciatic nerve.
- Piriformis syndrome is a condition that develops when the piriformis muscle, a small muscle that lies deep in the buttocks, becomes tight or spasms. This can put pressure on and irritate the sciatic nerve. Piriformis syndrome is an uncommon neuromuscular disorder.
- Cauda equina syndrome is a rare but serious condition that affects the bundle of nerves at the end of the spinal cord called the cauda equina. This syndrome causes pain down the leg, numbness around the anus and loss of bowel and bladder control.
What are the symptoms of sciatica?
The symptoms of sciatica include:
- Moderate to severe pain in lower back, buttock and down your leg.
- Numbness or weakness in your lower back, buttock, leg or feet.
- Pain that worsens with movement; loss of movement.
- “Pins and needles” feeling in your legs, toes or feet.
- Loss of bowel and bladder control (due to cauda equina).