Many times, three different types of herniations can be classified. The most common is often said to be a contained herniation or a protrusion or a bulge. This is when pressure in between the vertebrae causes the disc to protrude outwards, causing mild back or radiating pain complaints by compressing nearby nerves. Next is a disc extrusion or a non contained herniation, which causes considerably more pain. This type of extrusion is usually more severe, and may cause increased pain or even some neurological deficits in the patient with increased nerve pain. The third type is a sequestered herniation. This is usually when an extruded disc herniation goes unnoticed and the pressure of the surrounding vertebrae causes it to rupture, causing intense pain complaints. These disc herniations can occur in the cervical, thoracic or lumbar spine.