Sciatica is a medical condition associated with the sciatic nerve, the longest and thickest nerve in the human body. It runs down the back of the thighs and legs from the lower end of the spine.

Sciatica (sciatic pain) is not exactly a medical condition, but rather a symptom. The underlying medical condition could be --

1. Degenerative Discs Disease
This is a condition where the discs acting as a buffer between vertebrae wear out due to aging and lose their elasticity.

2. Herniated or Slipped Discs
In this condition, intervertebral discs damaged from degenerative disc disease or other causes may collapse or tear partially and fail to protect the spinal cord from coming into contact with bones and joints.

3. Any swelling or damage to the piriformis muscle located right next to the sciatic nerve can impact the latter and cause sciatic pain.

4. Narrowing of the spinal column, a condition called spinal stenosis, may also press on the sciatic nerve and spinal cord, causing sciatic pain.

5. Accidental injury to the lower back or spine may also cause sciatica.

Naturally, the appropriate causative factor has to be identified first to treat sciatica successfully.