There are generally four kinds of disc injuries. First, a disc can bulge. A bulging disc is a disc that's slightly out of place from its recommended or neutral place. After bulging, the second phase is herniation. A herniated disc is a tear in the lining of the disc, the outer part of the disc. After herniation, there's a protrusion. A rupture or protrusion is when the inside part, called the nucleus pulposus, leaks out and may touch a nerve. Finally, there is an extrusion. An extrusion is where the inner part is completely out, broken off, and floating within the spinal canal. When the disc comes out, it irritates nerves which can send nerve impulses. This can cause pain, burning, and tingling feelings either down your arms (if it's a neck injury) or down your legs (if it's a back injury). Learn More