Anatomy of finfish and shellfish

Unit 10 - Skeletal system

10.2.2. Vertebral Column
A series of endochondral bones called vertebrae form the vertebral column. Vertebrae have several common features. The large spool-shaped central portion of each is the centrum. Extending through the middle of each centrum is a canal for the passage of the notochord. As mentioned previously, many fish retain a notochord throughout life.
Above the centrum, an arch of bone surrounds and protects the spinal cord. A dorsal projection, the neural spine, extends outward from the vertebral column.The fish vertebral column is divided into two subdivisions: the trunk and the tail (caudal).
Although fish do not have a neck, the first two trunk vertebrae are modified. These vertebrae lack ribs. The rest of the trunk vertebrae possess ribs. Caudal (tail) vertebrae possess a ventral portion which forms a hemal arch which surrounds blood vessels.