Patients often state that they have been told they have arthritis of their spine and they ask, "What does that mean?"

Arthritis is a condition of joints in which there is wear and tear on the cartilage surface which leads to inflammation and pain.

To understand why people develop pain and stiffness in their spine as they age,  it is important to understand the function of the spine,  the process of aging,  the components that form the spine, and how the body responds to the wear and tear on the spine.

The function of the spine is to support the muscles of the body to allow us to walk and move.  To allow movement and transmit force,  the spine has developed individual motion segments or "joints".

Each spinal "joint" consists of two bones (vertebral bodies)  connected by a disc in the front and facet joints in the back.  These allow the spine to bend forward and backward,  side to side and twist.

The disc,  which connects the two vertebral bodies is arranged like a tire placed on its side.  Overlapping radial fibers (the annulus) provide strong attachments to the vertebral bodies and hold them in place.  Inside the rim of firm fibers is the soft gelatin-like material called the nucleus pulposus (the disc).  This soft material functions as a shock absorber.    As the body ages, (beginning early in the 30's) the fibers of the disc start to wear out.  When this occurs,  the annulus develops bulges and disc can be forced into these bulges.

The body adapts to this by increasing the surface of the vertebral bodies to allow the force to be shared over a larger area.   This leads to formation of spurs or osteophtes.  These osteophytes are a sign that the disc is aging and is not working as well as it previously had.

In the back of the spine are facet joints,   which are the same type of joint as the knee.  There is cartilage on the surface of each bone,  surrounded by a capsule and containing a small amount of lubricating fluid between the surfaces of the joint.  This allows the spine to slide forward and backward,  and bend and rotate.  These joints are subject to wear and tear.  When the disc in the front begins to wear   our,  there is more load in the joints in the back,  which can cause wear and tear in the cartilage.   Like knee joints,  as the cartilage gets worn and torn,  the facet joint can become painful and swollen.  These joints also develop spurs (osteophytes) as a natural response to the wear and tear.  Since the disc in the front and the facet joints in the back develop wear and tear,  the back muscles are under greater stress.   Unfortunately with aging,  the muscles also do not function as well as they did at an earlier age.  With age,  the muscles lose their elastic content and become shorter and stiffer.  This makes them less efficient and more prone to injury.   Furthermore,  since the joints in the spine are not functioning as well,   there are greater demands placed on the muscles.  This leads to the problems of back pain and neck pain that we see so commonly in patients in theirs 30's to 60's.

This combination of three natural processes wear and tear of the disc in the front,  wear and tear of the small joints in the back,  and the normal process of the aging of the muscles,  combine to make back pain and neck pain an almost universal problem in middle-aged adults.

Since the normal process of aging causes spur formation (osteophytes) around the spinal canal,  these spurs can start to impinge on either the spinal cord or the spinal nerve roots.  This is called  spinal stenosis. This is a normal process of aging and is not a problems for most people but can become a problems for some.  As the osteophytes grow bigger from wear and tear in the front and the back,  they can push on the nerve roots and cause pain or weakness.