The human vertebral column or spine is composed of numerous segments. Its main functions are to support the body, to cushion it (especially to protect the brain against shocks) and to protect the spinal cord.

The spine consists of 33-34 vertebrae, which are designated according to the region of the body in which they are found. We differentiate the following sections:

The cervical vertebral column with 7 cervical vertebrae.  The thoracic vertebral column with 12 thoracic vertebrae. The lumbar vertebral column with 5 lumbar vertebrae. The sacrum, that consists of 5 fused sacral vertebrae. The coccyx, that consists of 3 - 5 receded coccygeal vertebrae.

The individual vertebrae are separated from one another by intervertebral discs. They function like shock absorbers. Intervertebral foramen  allow the spinal nerves to leave the vertebral canal.

Facet joints (articulationes zygapophysiales) have an influence on movement in the individual sections of the vertebral column. They are among the synovial joints of the human body. Various ligaments (syndesmoses) between the vertebral processes cover almost the entire vertebral column.

The vertebrae above the sacrum are termed free vertebrae (praesacrale). They form the free vertebral column that makes up approximately 35% of the body length of the adult (55-63 cm long).

When the body is standing upright, the vertebral column of an adult is shaped in a double-S curve (it is simply S-shaped with four-footed animals). It has two convex curves towards the front, which is normal for the cervical and lumbar vertebral column (cervical and lumbar lordosis).

Two concave curves towards the front are the normal curves for the thoracic vertebral column and sacrum (cervical and sacral kyphosis). However, lateral curvature in the vertebral column (scoliosis) always deviates from the norm.