How herniated nucleus pulposus develops?

A disc herniation: The nucleus pulposus is the middle soft part of the disc in the spine that normally acts like a cushion. It looks and feels like a thick jelly material. Sometimes, it can leak out if there is a tear in the outside part of the disc (called the annulus fibrosus). When it leaks out, it can pinch a nerve and cause pain that radiates into the extremities.