A top down view reveals a cross section at the disc level of the diagram above. This diagram on the is essentially the drawing of a ring. The ring is the disc in the front and the lamina, and spinous process above, and the facet joints on either side. The normal space available for the nerves and the sac is taken up by the bone spurs from the sides, the bulging disc or spurs from the floor and the thick ligament or spurs from the roof.