Section I. GENERAL
a. Spinal Column. The spinal column (also called the backbone, spine, or
vertebrae column) consists of a series of bones called vertebrae (see figure 2-1) and
fibrocartilage layers (intervertebral disks) that separate adjacent vertebrae. The
vertebrae are held together by ligaments. The top seven vertebrae (cervical vertebrae)
are the bones of the neck. The next twelve vertebrae (thoracic vertebrae) form the
upper part of the back and have the ribs attached. The next five vertebrae (lumbar
vertebrae) form the lower part of the back. The next five vertebrae (sacral vertebrae)
are located between the hip bones. They are fused together and form the sacrum, a
structure that looks like a broad triangle. The final four vertebrae (coccygeal vertebrae)
are fused rudimentary vertebrae located at the end of the sacrum. These rudimentary
vertebrae form the coccyx.
b. Spinal Canal. The spinal canal is created by holes in the posterior parts of
the vertebrae. The spinal canal contains the spinal cord.
Figure 2-1. The spinal column and a typical thoracic vertebra.