Kyphosis can be a confusing medical term because it's also used as a description of a spinal curve. In fact, even people with healthy spines have a kyphotic curve, as you'll learn in the Anatomy of Kyphosis article. Your mid-back region (thoracic spine) is supposed to curve outwards, or have a kyphotic curve. However, too much kyphosis in the thoracic spine is abnormal, and it's called hyperkyphosis, problematic kyphosis, or abnormal kyphosis. (In this article series, we'll call an extreme kyphotic curve abnormal kyphosis.)
Some people may call abnormal kyphosis just plain slouching, but it is more than that. It changes the way your spine works, and it can be very painful.
There are two types of abnormal kyphosis: structural and postural.