In the normal state, the dorsal spine (located between the neck and the lower back) presents a curvature with posterior convexity. Conversely, the region of the neck and lower back present a curvature with anterior convexity.

Kyphosis is an exaggeration of the convexity of the dorsal region giving the back an overly rounded position. The cervical and lumbar parts of the spine present an exaggerated arch to counterbalance the dorsal convexity associated with kyphosis.

Kyphosis can be associated with scoliosis (lateral deviation of the spine) resulting in kyphoscoliosis.

There are several types of kyphosis:

a) kyphosis of children and adolescents. It may be due to:

– a bad position: it is most often linked to insufficient back strength training. No significant deformity of the bones of the spine is identifiable.

-Scheuermann’s disease: it is due to an anomaly in the growth of the dorsal vertebrae. The cause of this disease remains unknown. It affects boys more often than girls. It associates back stiffness, increased pain after prolonged sitting or physical exercise. The aesthetic deformity of the patient’s back is most often marked. An x-ray examination of the spine makes it possible to make the diagnosis by showing a deformity affecting at least three consecutive dorsal vertebrae. The course of the disease ceases at the end of growth, but the vertebral anomalies linked to the disease remain irreversible.

b) kyphosis of young adults is most often a symptom of an inflammatory rheumatic disease called ankylosing spondylitis. This disease mainly affects the pelvis and the spine and can associate a set of symptoms: joint pain occurring especially at night, back stiffness, fever, fatigue, intestinal disorders. Its development is chronic and in spurts.

c) kyphosis in the elderly may be related to:

-a vertebral osteoporosis responsible for weakening of the vertebrae and vertebral compression

-a degeneration of the intervertebral discs (a kind of pads located between each of the vertebrae)

Other causes, rarer, can be responsible for kyphosis:

-a trauma

– neuromuscular disease (such as polio)

-a congenital malformation