What is Sciatica?
Sciatica is pain in the lower extremity resulting from irritation of the sciatic nerve. The pain of sciatica is typically felt from the low back (lumbar area) to behind / side of the thigh and can radiate down below the knee to the foot. The sciatic nerve is the largest nerve in the body and begins from nerve roots in the lumbar spinal cord in the low back and extends through the buttock area to send nerve endings down the lower limb.
While sciatica is most commonly a result of a lumbar disc herniation directly pressing on the nerve, any cause of irritation or inflammation of the sciatic nerve can produce the symptoms of sciatica. This irritation of nerves as a result of an abnormal intervertebral disc is referred to as radiculopathy. Aside from a pinched nerve from a disc, other causes of sciatica include irritation of the nerve from adjacent bone, tumors, muscle, internal bleeding, infections in or around the lumbar spine, injury, and other causes. Sometimes sciatica can occur because of irritation of the sciatic nerve during pregnancy.
Sciatica causes pain, a burning sensation, numbness, or tingling radiating from the lower back and upper buttock down the back of the thigh to the back of the leg. The result is lumbar pain, buttock pain, hip pain, and leg pain. Sometimes the pain radiates around the hip or buttock to feel like hip pain. While sciatica is often associated with lower back pain (lumbago), it can be present without low back pain. Severe sciatica can make walking difficult if not impossible. Sometimes the symptoms of sciatica are aggravated by walking or bending at the waist and relieved by lying down. The pain relief by changing positions can be partial or complete.
Another cause of sciatica is the Piriformis syndrome.
The piriformis is a muscle which extends from the side of the sacrum to the top of the thigh bone at the hip joint. The sciatic nerve can either pass over, through or under the periformis muscle. When a short or tight piriformis is stretched, it can compress and irritate the sciatic nerve. Because the piriformis muscle acts to rotate the leg outward (like kicking a ball) people who habitually stand with their toes turned out often develop Piriformis syndrome.