The Vertebral Column

The Vertebral Column

The vertebral column, or backbone (Figure 9.8), is made of 33 serially arranged vertebrae, each pair interconnected by a cartilaginous pad, the intervertebral disc, which cushions and permits limited movement between adjacent vertebrae. It runs from the base of the skull to the pelvis, forming the structural core of the trunk, and is organised into five regions: Cervical, Thoracic, Lumbar, Sacrum and Coccyx. In an infant the sacrum begins as 5 separate sacral vertebrae and the coccyx as 4 separate coccygeal vertebrae; in the adult, each group fuses into a single bone (the sacrum and the coccyx respectively).

Each individual vertebra has a central hollow opening, the neural canal, through which the spinal cord passes. The first vertebra, which supports the skull, is called the atlas; the second is the axis. The atlas articulates directly with the occipital condyles of the skull, allowing the nodding motion of the head, while the pivot joint between atlas and axis allows the head's side-to-side rotation. …