“I’ve got it again with sciatica” – when Aunt Käthe used to complain as usual in winter, people would imitate her crooked posture behind her back, giggling. Decades later, this childhood memory resurfaces as a sudden pain pulls at the leg while hauling boxes. “Sciatica” is first of all short for the sciatic nerve, the longest and thickest nerve in humans. It arises bilaterally from the lumbosacral plexus, a nerve plexus formed by many spinal cord nerves at the level of the sacrum. The sciatic nerve travels along the buttocks and the back of the thigh – whose flexor it supplies – to the back of the knee, where it splits into the tibial and calf nerves, supplying the muscles and skin of the lower leg and foot. It is not uncommon for disorders to occur in the course of the sciatic nerve, which can lead to typical pain and deficits. This is called sciatica syndrome, popularly abbreviated as “sciatica” as well.
How does sciatica syndrome develop?
By far the most common cause is disorders of the lower lumbar spine. The bony processes on the vertebrae connect the adjacent vertebrae in a movable manner. Between them are recesses through which the spinal cord nerves emerge; these sites are also called nerve roots.
If there are signs of wear and tear on the intervertebral discs (as in the case of a herniated disc) and/or the vertebral bodies, these intervertebral holes can narrow in such a way that the nerve roots are squeezed there. Due to the anatomical conditions, the area at the transition from the lumbar spine to the sacrum is particularly frequently affected, i.e. where the nerve root of the sciatic nerve is located. If there is a constriction, abrupt movements, twisting or lifting a heavy load can cause an attack of discomfort.
Other triggers for nerve irritation are cool drafts, especially after being soaked (e.g., sitting on a cold rock with a wet bathing suit), or pressure on the nerve fibers from a tumor in the pelvis or from the unborn child during pregnancy. Less common causes include nerve inflammation from infections such as shingles, damage from chronic diseases such as diabetes mellitus and rheumatism, or bone injuries to the hip.
