Scheuermann's disease is a spinal deformity in which the front of the spine does not grow as quickly as the back, causing excessive curvature of the thoracic spine (kyphosis). It typically occurs during periods of bone growth between ages 12-14. Symptoms may include back pain, difficulty breathing, and muscle spasms. Treatment depends on the degree of curvature but may include exercises, bracing, medication, or surgery to reduce the deformity.