Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Back pain is an ache felt in the back that usually originates from the muscles, nerves, bones, joints or other structures in the spine. Back pain may arise suddenly or may be chronic. Chronic back pain can itself be constant or intermittent, stay in one place or expand to other areas such as the arms and hands as well as the legs or feet, and may include symptoms other than pain, such as weakness, numbness or tingling. Back pain is one of humanity's most frequent complaints. For instance, acute low back pain lumbago is the fifth most common reason for physician visits in the United States and about nine out of ten adults experience back pain at some point in their life...