Kyphosis is caused by any condition that deforms the bones of the thoracic part of the spine so that the person is bent forward. There are two common forms of kyphosis encountered in the population: Scheueremann's kyphosis and postural kyphosis.

Scheueremann's kyphosis is most common in teenage boys. It is characterized by a short, sharp kyphosis in the middle part of the upper spine, and may be associated with aching back pain. The kyphosis tends to be rigid on clinical examination and it can be seen on the x-ray.

Postural kyphosis is condition of the dorsal spine resulting from an extreme curvature of the spine that is not associated with pain. The curve is easily corrected by asking the patient to stand up straight. Kyphosis can also be corrected with plaster-jacket supports, pads and braces.