Treatment Options Spine Anatomy Introduction The spine is made up of a series of connected bones called "vertebrae," which encircle and protect the spinal cord. The disc is a combination of strong connective tissues that hold one vertebra to the next, and acts as a cushion between the vertebrae. Nerves branch from the spinal cord and pass through openings in the vertebrae to other parts of the body. Several of these nerves join at the base of the spine to form the sciatic nerve, which runs down the leg. In this section you can read more about the structure and anatomy of the spine. Section I contains drawings of normal spine anatomy. Section II features drawings and descriptions of abnormal spine disorders.