According to Houston Methodist Orthopedics and Sports Medicine, Scheuermann's disease is an exaggerated outward curve of the spine between the base of the neck and the bottom ribs. Though it occasionally develops in adults, the disease typically starts between the ages of 10 and 12. The cause is unknown.
The standard curve of the spine's midsection is between 25 and 40 degrees, explains Houston Methodist Orthopedics and Sports Medicine. With Scheuermann's disease, this curve exceeds 45 degrees. Normally, the small bones, or vertebrae, that compose the spine should be round, while with Scheuermann's disease, vertebrae are wedge-shaped. This forces the midsection to curve more than it should. If untreated, the condition generally leads to spinal deformity and back pain.