The lumbar spine provides both stability and support, allowing humans to walk upright. Proper function of the lumbar spine requires that it have a normal posture (ie, a normal lumbar curve). Any injury that changes the shape of a lumbar vertebra will alter the lumbar posture, increasing or decreasing the lumbar curve. As the body attempts to compensate for the alteration in the lumbar spine in order to maintain an upright posture, this will tend to distort the curves of the thoracic and cervical spine.