This condition begins in childhood or adolscence (often 10 to 12 years) and tends to increase progressively until skeletal growth is complete. It can lead to severe deformity, especially when the chest (thoracic) region is affected. In adults with longstanding deformity it may be accompanied by pain.
The skeleton (from the photographs) exhibits mainly a thoracic scoliosis with the curve to the right. This would be accompanied by rotation of the vertebrae on a vertical axis, thrusting the ribs backwards on the convex side, increasing the appearance of the deformity.
The cause is unknown.
Dr. F. J. Fox