The vertebral column (columna vertebralis) forms the lower infracranial part of the axial skeleton. It provides a strong and flexible support of the trunk and also transmits and protects the spinal cord and the roots, stems and branches of the spinal nerves.
The vertebral column extends from the base of the skull, through the neck, trunk, and it ends at the level of the floor of the pelvis. The vertebral column is composed of 33 to 34 vertebrae, which can be subdivided into five regions.
Within each region, the vertebrae are numbered from the superior to the inferior relations as follows:
- cervical vertebrae (vertebrae cervicales) – (7)
- thoracic vertebrae (vertebrae thoracicae) – (12)
- lumbar vertebrae (vertebrae lumbales) – (5)
- sacral vertebrae (vertebrae sacrales) in the adult – (5); the sacral vertebrae from S1 to S5 fuse with each other to form one bone called the sacrum (os sacrum)
- coccygeal vertebrae (vertebrae coccygeae) in the adult – (3-5); like the sacrum, it forms one bone from fused coccygeal vertebrae called coccyx (os coccygis).
In the articulated vertebral column in the adult body four normal curvatures located in midsagittal plane can be seen.
- cervical lordosis – concave posteriorly and convex anteriorly.
- thoracic kyphosis – concave anteriorly and convex posteriorly.
- lumbar lordosis – concave posteriorly and convex anteriorly.
- sacral kyphosis – concave anteriorly and convex posteriorly.
Primary curvatures develop prior to birth and exist in the thoracic and sacral regions. They form ventral concavity.
Secondary curvatures develop during infancy and exist in the cervical and lumbar regions. They form dorsal concavity.
Lordosis and kyphosis alternate down the spine. But how do you remember which is first? Remember the lord is highest up… So LORDOSIS comes first.
Clinical comments
The pathological, abnormal lateral curvature of the vertebral column is called scoliosis.Structure of a typical vertebra.