What Is Sciatica?
In evaluating patients in the office, we doctors must always keep a very open mind. For example, when a patient says that their problem is located in a certain area, they may use laymen's terminology that is technically inaccurate, they may have forgotten certain characteristics of the condition because of lack of sleep or pain, or the problem may feel like it comes from a certain location yet it may actually be coming from an area of the body far from where it is perceived. This last situation is commonly the case when a person has sciatica.
Sciatica is pain resulting from irritation of the sciatic nerve. Sciatica pain is typically felt from the low back to behind the thigh and radiating down below the knee. 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.
What Causes Sciatica Symptoms?
However, some people only experience pain or numbness in the calf of the leg, or in the foot, while the source of the problem is actually located in the low back. This is because sciatica is most commonly a result of a lumbar (low back) disc herniation directly pressing on the sciatic nerve. Moreover, any cause of irritation or inflammation of this nerve as it comes out of the spine in the low back can reproduce the symptoms of sciatica. Other causes include irritation of the nerve from adjacent bone, tumors, muscle, internal (pelvic) bleeding, infections, and injury.
Irritation of the sciatic nerve from any of the causes described above can lead to sciatic pain, a burning sensation, numbness, or tingling that radiates from the lower back and upper buttocks down the back of the thigh to the back of the leg. 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.
Clinical Primer of Rheumatology, Lippincott Williams & Wilkens, edited by William Koopman, et al., 2003.
Kelley's Textbook of Rheumatology, W B Saunders Co, edited by Shaun Ruddy, et al., 2000.