Description
The vertebral column (or spine) consists of the 33 vertebrae that provide the framework for the central axis of the axial skeleton.
For classification purposes, the vertebral column can be arbitrarily divided into five regional groups. From superior to inferior, these are the:
- seven cervical vertebrae;
- twelve thoracic vertebrae;
- five lumbar vertebrae;
- five sacral vertebrae;
- four coccygeal vertebrae.
Twenty-four of these vertebrae (i.e., the cervical, thoracic, and lumbar) are unfused and are known as true vertebrae. They become progressively larger from superior to inferior. The remaining nine vertebrae (i.e., the sacral and coccygeal) are fused and are known as false vertebrae. They become progressively smaller from superior to inferior. The fused sacral vertebrae collectively form the sacrum, while the fused coccygeal vertebrae collectively form the coccyx.
When viewed laterally, the full length of the adult vertebral column is seen to have four curvatures:
- cervical lordosis;
- thoracic kyphosis;
- lumbar lordosis;
- sacral kyphosis.
Regarding function, the vertebral column:
- protects the spinal cord, which travels through its vertebral canal;
- provides structural support to the head, neck and trunk and helps maintain posture;
- is capable of flexion, extension, lateral flexion and rotation movements.
Related parts of the anatomy
