Sciatica refers to the pain that radiates along the path of the sciatic nerve, which is the longest nerve in the body. It usually starts in the lower back and extends down the back of each leg. Here's a brief overview of sciatica:

Causes: 

Sciatica is often caused by compression or irritation of the sciatic nerve. The most common causes include:

Herniated or slipped disc: When the gel-like material inside a spinal disc leaks out and puts pressure on the nearby nerve roots, including the sciatic nerve.

Spinal stenosis: Narrowing of the spinal canal, which can exert pressure on the sciatic nerve.

Piriformis syndrome: Irritation or compression of the sciatic nerve by the piriformis muscle in the buttocks.

Spinal injury or trauma: Fractures, dislocations, or other spinal conditions that affect the sciatic nerve.

Degenerative disc disease: Age-related wear and tear of the spinal discs, leading to nerve compression.

Symptoms: 

The hallmark symptom of sciatica is pain that radiates from the lower back through the buttock and down the back of one leg. Other common symptoms include:

• Sharp, shooting pain along the affected leg.

• Numbness or tingling sensation in the leg or foot.

• Weakness or difficulty with foot or leg movement.

• Pain that worsens with sitting, standing, walking, or sudden movements.

• Symptoms typically occur on one side of the body.