Slippage of a vertebra (anterolisthesis). Coloured magnetic resonance imaging (MRI) scan showing anterolisthesis in a 52-year-old woman's back. Anterolisthesis is where a vertebra slips forward relative to the vertebrae beneath it. Here vertebra L4 (4th lumbar) has slipped forward on vertebra L5 below (lower centre), and the intervertebral disc between them has also collapsed. The slippage often occurs as a result of bone fractures and symptoms depend on the severity of the slippage. Symptoms can involve movement problems, problems feeling sensations (such as heat or pain), loss of bladder or bowel control, poor posture and pain. Treatment can include interbody fusion, a surgical procedure to place a bone graft between adjacent vertebrae.