lumbago /lumbā″gō/ [L, lumbus, loin] , pain in the lumbar region caused by a muscle strain, rheumatoid arthritis, osteoarthritis, or a herniated intervertebral disk. Ischemic lumbago, characterized by pain in the lower back and buttocks, is caused by vascular insufficiency, as in terminal aortic occlusion. See also low back pain.
