What is Kyphosis?

The spine has a series of normal curves when viewed from the side. These curves help to better absorb the loads applied to the spine from the weight of the body. The cervical spine (neck) and lumbar spine (lower back) are have a normal inward curvature that is medically referred to as lordosis or "lordotic" curvature by which the spine is bent backward. The thoracic spine (upper back) has a normal outward curvature that is medically referred to as kyphosis or the "kyphotic" curve by which the spine is bent forward.
The spine is normally straight when looking from the front. An abnormal curve when viewed from the front is called scoliosis. Scoliosis can occur from design at birth or from rotation or an abnormal twisting of the vertebrae as from pain.

The normal curves of the spine allow the head to be balanced directly over the pelvis. If one or more of these curves is either too great or too small, the head may not be properly balanced over the pelvis. This can lead to back pain, stiffness, and an altered gait or walking pattern.

What are the symptoms of kyphosis?
The most common symptoms for patients with an abnormal kyphosis are the appearance of poor posture with a hump appearance of the back or "hunchback," back pain, muscle fatigue, and stiffness in the back. Most often, these symptoms remain fairly constant and do not become progressively worse with time.

In more severe situations, the patient may notice their symptoms worsening with time. The kyphosis can progress, causing a more exaggerated hunchback. In rare cases, this can lead to compression of the spinal cord with neurologic symptoms including weakness, loss of sensation, or loss of bowel and bladder control. Severe cases of thoracic kyphosis can also limit the amount of space in the chest and cause cardiac and pulmonary problems leading to chest pain and
What causes abnormal kyphosis? What are the types of kyphosis?

There are three main types of abnormal kyphosis: postural kyphosis, Scheuermann's kyphosis, and congenital kyphosis.
Postural kyphosis is the most common type of kyphosis. This is more common in girls than in boys and is typically first noticed during adolescence. It is caused by poor posture and a weakening of the muscles and ligaments in the back (paraspinous muscles). The vertebrae are typically shaped normally in postural kyphosis. It is often slow to develop and usually does not continue to become progressively worse with time. These patients can have symptoms of pain and muscle fatigue. This type of kyphosis does not lead to a severe curve with a risk of neurologic, cardiac, or pulmonary problems.

Scheuermann's kyphosis also is first noticed during adolescence. This type of kyphosis is the result of a structural deformity of the vertebrae. It is more common to develop scoliosis (kyphoscoliosis) with Scheuermann's kyphosis than with the other types of kyphosis. The diagnosis requires X-rays to show a wedge of at least 5 degrees at the front of at least three neighboring vertebral bodies. The reason for this abnormal wedging of the vertebrae is not well understood.

Congenital kyphosis is the least common type of abnormal kyphosis. This is caused by an abnormal development of the vertebrae during development prior to birth. This can lead to several of the vertebrae growing together (fusing) in kyphosis.

There are other disorders that can lead to kyphosis in adults. The most common of these is from sustaining multiple compression fractures of the bony building blocks of the spine (vertebrae) from osteoporosis. Other causes include degenerative arthritis, ankylosing spondylitis, spine infections, and spine tumors. Each of these disorders can lead to a collapse of the front of the vertebrae and the development of kyphosis.

Medical Author: Jason C. Eck, DO, MS
Medical Editor: William C. Shiel Jr., MD, FACP, FACR