Disc herniation is simply a rupture in the inter-vertebral disc. The disc has a soft, jelly like center called the nucleus pulposus encased in a hard protective casing called the annulus fibrosus. In herniated discs, the nucleus projects through the ruptured annulus.

You are most likely to find a herniated disc in the lumbar spinal area, usually in the discs between L4 - L5 and L5 - S1 vertebrae. The discs start losing elasticity and water content with age, and people between 30 and 50 appear mostly at risk.

Disc herniation occurs in four progressively severe and distinct stages -

# Disc Protrusion
# Disc Prolapse
# Disc Extrusion
# Sequestered Disc

The first two stages are referred to as incomplete and the last two, complete herniation.

Disc herniation is accompanied by pain of varying degree. There may be muscle spasms and other sensory deficiencies caused by radicular pain like tingling and numbness.

Herniated disc can be diagnosed by a combination of physical examination (like Lasegue Test) and diagnostic procedures (like X-rays, CAT and MRI). When the doctor's findings from physical examination match that from the other tests, diagnosis is complete.