Curvature of the spine

The spine belongs together with the skull to the axial skeleton. It has physiological curvatures that change during ontogeny. The curvatures in the sagittal plane are:


 * Lordosa – forward convex curvature. Lordosa is strengthened by the action of certain muscle groups. The lordosis is not completely fixed until the age of six.
 * Kyphosis – antagonistic curvature of the lordosis (convex backward ). Unlike lordosis, it is not actively formed by muscles, but is a remnant of the original kyphotic curvature of the entire spine.

Physiological curvatures
Lordosis and kyphosis alternate on the spine in this sequence:


 * Cervical lordosis – its peak is at the level of 4.-5. cervical vertebra ; it develops in the child when he raises his head from the position on his stomach.
 * Thoracic kyphosis - has a peak at the 6th-7th. thoracic vertebra.
 * Lumbar lordosis - with a peak at the level of 3.-4. lumbar vertebra. It develops especially when the child is learning to stand and walk.
 * Promontorium – or kyphotic bend of the spine between the last lumbar vertebra and the basis ossis sacri.

Scoliosis
Scoliosis is curvature in the frontal plane (to the sides). The human spine usually has a slight physiological curvature, especially in the area between the 3rd and 5th thoracic vertebrae. The increase of this deflection above a certain value is a negative phenomenon that must be addressed. Scoliosis is usually accompanied by rotation of the vertebrae.

Scoliosis can also be a temporary phenomenon, for example when a person stands on one leg or carries a heavy load in one hand.

Incorrect curvatures of the spine
Pathological curvatures are mainly caused by weak muscles. We recognize several types:


 * Flat back – the spine has reduced physiological kyphosis and lordosis (especially thoracic and lumbar). They occur when the muscles are weak.
 * Arched back - they have a more pronounced curve. They are formed as a reaction to the long-term pull of powerfully developed back muscles.
 * Round back - thoracic kyphosis increases. A round back arises from several causes: as a result of weak neck muscles with simultaneous faulty posture of the spine while standing or sitting. Furthermore, they can be caused by one-sided permanent load, e.g. during work. This curvature often arises even in old age due to the reduction of the intervertebral discs.

Related Articles

 * Scoliosis
 * Wrong body posture