Stenosis is commonly caused by an excess growth of bone around the spinal nerves. This excess bone growth often results from osteoarthritis. Stenosis can also result from a dislocation or a fracture of the vertebral bone. Stenosis can be caused by soft tissue intruding into the spine's open spaces. Herniated discs, tumors, and thickened spinal ligaments can press against the spinal nerves. And in some cases, a person is born with a small spinal canal that does not provide enough room for the spinal nerves.