The spine is made up of a column of 33 individual bones, called vertebrae, which are stacked atop one another to provide the entire body with structure and support. The spine has a series of normal curves when viewed from the side. These curves help absorb the loads applied to the spine from the weight of the body. The cervical spine (neck) and lumbar spine (lower back) normally have a lordotic, or inward, curvature. The thoracic spine (upper back) normally has an outward kyphotic curve.

Kyphosis is change of the forward/outward curvature of the thoracic spine. Most often the curvature is exaggerated which creates a hunched-back effect. Lordosis is change of the inward curvature of the lumbar or cervical spine. For the lumbar spine, this is most commonly an exaggeration of the curve, causing an arched back. For the cervical spine, it is more common to see loss of curve making it difficult to look over the shoulders. Treatment for any of these conditions is a rigorous physical therapy and home exercise program as well as bracing and treating an underlying condition such as osteoporosis.

Common causes of any of these deformities of the natural curvature of the spine include obesity, osteoporosis, and poor posture.

Symptoms for Kyphosis include a hunched back appearance. Symptoms for  Lordosis include exaggerated posture such that there is a gap beneath the back when lying on the floor. Flat back syndrome is where there is a loss of either or both of these curves.