It is a condition in which one bone in your back, vertebra slides forward over the bone below it. It most often occurs in the lower spine. Sometimes when a vertebra slips out of place you may have no symptoms at all or no symptoms year later. Causes it may be caused by any no. of problems with the small joints in your back. 1. A defective joint where that you have had since birth 2. A joint damaged by an accident or by trauma 3. A vertebra with a stress fracture 4. A joint damaged by an infection or arthritis Symptoms & Science 1. Back pain 2. The pain that runs from the lower back down one or both legs 3. Numbness or weakness in one or both legs 4. Difficulty walking 5. Leg back pain that gets worse when you bend over or twist. 6.Loss of bladder or bowel control. Diagnosis 1. X-rays 2. CT 3. MRI 4. Treatment It begins with stopping any physical activity that may have led to vertebral damage.Use of pain killers & Physical therapy.