Joint disease. Coloured 3-D computed tomography (CT) scan of the lower thoracic and upper lumbar region of the spine in side (sagittal) view, showing arthrosis of the vertebrae. Arthrosis is a degenerative joint disease causing damage to the cartilage and bones of a joint. The vertebrae of the spine (down left) are separated by cartilage, which may be worn away. New bone or cysts may form at the joints. At upper centre, new bone growth appears to impinge on the abdominal aorta (pink). The abdominal aorta is the largest artery below the diaphragm. It carries blood to the abdominal organs before dividing to form the iliac arteries of the legs. The ribs of the chest are at right.