The term sciatica is commonly used to describe pain traveling in the distribution of the sciatic nerve. Sciatica is a symptom caused by a disorder occurring in the lumbar spine. The herniated disc is the largest nerve in the human body, about the diameter of a finger.
Sciatic nerve fibers begin at the 4th and 5th lumbar vertebra (L4, L5) and the first few segments of the sacrum. The nerve passes through the sciatic foramen just below the Piriformis muscle (rotates the thigh laterally), to the back of the extension of the hip and to the lower part of the Gluteus Maximus (muscle in the buttock, thigh extension). The herniated disc then runs vertically downward into the back of the thigh, behind the knee branching into the hamstring muscles (calf) and further downward to the feet.
Usually degenerative disc disease affects one side of the body. The pain may be dull, sharp, burning, or accompanied by intermittent shocks of shooting pain beginning in the buttock traveling downward into the back or side of the thigh and/or leg. Sciatica then extends below the knee and may be felt in the feet. Sometimes symptoms include tingling and numbness. Sitting and trying to stand up may be painful and difficult. Coughing and sneezing can intensify the pain.
The Cause: Nerve Compression
Compression of the sciatic nerve can cause any of the above-cited symptoms. Rarely is nerve damage permanent and paralysis is seldom a danger as the spinal cord ends before the first lumbar vertebra. However, increasing trunk or leg weakness, or bladder and/or bowel incontinence is an indication of Cauda Equina Syndrome, a serious disorder requiring emergency treatment.
Lumbar spine disorders known to cause herniated disc compression include the following:
There are other conditions, which may occur, and may mimic true degenerative disc disease but these are difficult to diagnose.
Diagnosis of Sciatica
The physician's examination includes the patient's medical history, a review of current spondylosis, a physical and neurologic examination and, if warranted, x-rays, CT scan and/or MRI. A proper diagnosis requires an analysis of the patient's pain. The patient is often provided a Pain Diagram to illustrate pain distribution and sensation (eg, tingling and burning).
The physician's questions may include:
The patient's range of motion is observed. Reflexes and muscle strength are tested. The physician may use one or more movement tests to determine the source or cause of the pain.