This condition develops over time during periods of bone growth (such as puberty). It occurs when the front of the spine doesn’t grow as fast as the back of the spine and causes healthy, rectangular-shaped vertebrae to become triangular-shaped and wedged together. This causes the thoracic spine to curve more than normal. Patients become stooped forward with a bent-over posture. The ends of your ribs, although not attached to the spine, rest in indentations in the thoracic vertebrae that help support the ribs. Symptoms may include: Pain in the upper back, numbness, pain or tingling from the upper back and around the chest, leg weakness and chest pain.