Scoliosis is a pathological curvature of the spine towards one side of the body. The term is derived from Ancient Greek skolios - “crooked”, and was probably coined by the great physician Galen (131 – 201 AD).
Scoliosis may or may not be structural. Structural scoliosis is caused by structural changes to the vertebrae or their abnormal rotations or asymmetries. Non-structural scoliosis has no basis in the anatomy of the spine itself, and the vertebrae are normal. Instead, the scoliosis is due to secondary causes, such as lumbar muscle contracture, substantially mismatched leg lengths, skewed pelvis, etc.