Scoliosis (/ˌskoʊlɪˈoʊsɪs/; from Ancient Greek: σκολίωσις skoliosis "bending") is a common medical condition in which a person's spinal axis has a three-dimensional deviation. Although it is a complex three-dimensional condition, on an X-ray, viewed from the rear, the spine of an individual with scoliosis can resemble an "S" or a "C", rather than a straight line.