the back, and the sacral with the hips. The caudal vertebrae form the tail; some dinosaur tails, particularly those of sauropods, were long because of a large number of vertebrae (Chapter 10). Three or more sacral vertebrae, in association with the hips of a dinosaur, comprise another defining characteristic (Fig. 5.3).
Each vertebra has a central part (appropriately named a centrum), an arch dorsal to the centrum (the neural arch), and a hollow area between the centrum and neural arch (the nerve or spinal canal) where a dinosaur's nerve cord was located. Vertebrae also have different knobs emanating from them called processes that articulated with one another or with ribs (also known as costae); the latter places of articulation are called transverse processes. Ventral and medial to the paired ribs of some dinosaurs are smaller ribs called gastralia that evidently lent support to dinosaur bellies. Caudal vertebrae were reinforced by tendons in some dinosaurs, such as hadrosaurs (Chapter 11) and a few theropods (Chapter 9). Some long-tailed dinosaurs, such as sauropods (Chapter 10), also had bones ventral to the vertebrae called chevrons. Chevrons probably protected blood vessels on the ventral part of the tail.
Was this article helpful?