Sciatica is a painful condition in which discomfort travels from the lower back down through one or both legs. The pain may feel sharp, burning, stabbing, tingling or electric in nature, often worsening with sitting, bending or sudden movement. Unlike ordinary back pain, sciatica follows the pathway of a major nerve and can significantly limit daily activity.
Sciatica occurs when excessive pressure is placed on the sciatic nerve, the longest and thickest nerve in the human body. This pressure interrupts normal nerve function, triggering pain, weakness, numbness and altered sensation in the lower body.
The sciatic nerve originates in the lower spine and exits the spinal column through small openings between the vertebrae. Any narrowing, swelling or damage in this region can irritate the nerve and begin the cascade of sciatica symptoms.
After leaving the spine, the sciatic nerve travels through the hips and buttocks, then branches down each leg, extending into the calves, ankles and feet. This long pathway explains why sciatica pain can be felt across such a large area of the body.
One of the most common causes of sciatica is a spinal disc herniation. The soft gel-like centre of the disc can leak outward, pressing against nearby nerve roots and causing intense inflammation and pain along the sciatic pathway.
When nerve compression becomes severe, people may experience sudden, sharp, shooting pain accompanied by muscle weakness, burning sensations or pins-and-needles feelings. These symptoms often worsen when standing, coughing or moving abruptly.
Sciatica that originates at the L3–L4 level of the lower back affects specific nerve pathways. This location commonly produces pain, tingling and weakness in the front thigh, knee and parts of the lower leg.
As nerve signals become impaired, pain and numbness may spread into the middle portion of the foot and toes. Many patients describe this as a constant pins-and-needles sensation or partial loss of feeling in the affected areas.
In advanced cases, sciatica may limit your ability to lift the leg properly. Knee reflexes can weaken or disappear altogether, making walking, standing or climbing stairs difficult and unsafe.