The spinal column is made out of vertebrae that are separated from each other by cartilage discs. These discs absorb the shock to the spinal column, acting as cushions. If for any reason these discs get damaged or degenerate, they can tear and the center part of these disks can pop out, compressing the spinal nerves. This condition is known as spinal disc herniation. https://www.painfreenyc.com/herniated-disc/