Aherniated disc is an injury of the pads of cartilage between the vertebrae in which the cartilage bulges from normal position. what type of cartilage is affected?

The answer to this question would be fibrous cartilage.

Fibrous is a connective tissue that used for protecting. It found mostly in the joint where it helps bind it up so the joint will not dislocate. In this case, the fibrous tissue is protecting the vertebrae so it won't slide to the front, back or the side. If vertebrae moved from its normal position, it can cause pain to the back.