Sciatica pain is intense, radiating pain that runs from the lower back through the buttock, leg, and down into the foot. It occurs when the sciatic nerve is compressed or irritated somewhere along its path from the lower lumbar vertebrae and sacrum, where it originates, through the buttock and thigh, and further down to the lower leg and foot.

Pressure or stretching of the nerve can cause sharp, stabbing pain, often accompanied by tingling, sensory disturbances, or reduced strength in the leg. In severe cases, the leg may give way, making it difficult to stand or walk.

In most cases – about 90 percent – sciatica is caused by a disc pressing on the nerve in the lower back or by compression of the nerve in the buttock due to tight muscles. Other causes can include osteoarthritis, inflammation, overuse, or, in rare cases, a tumor. Many hours of heavy lifting or sedentary work can irritate the discs, while prolonged strain on the gluteal muscles – for example from running or sitting with crossed legs – can compress the nerve.

Sciatica is also common during pregnancy, as increased pressure in the abdomen and pelvis can affect the nerve, while the pelvis loosens and the body’s load changes.

It is important to distinguish sciatica pain from ordinary back or leg pain. Only when the sciatic nerve itself is involved and the pain radiates down the leg is it considered true sciatica. Other conditions such as spinal stenosis, vertebral slippage, scar tissue after a herniated disc, or tight connective tissue can cause similar symptoms.