Dinosaurs, in general, seem to have been relatively healthy animals, if the evidence from—and the interpretation of—the fossil records are to be believed. A few fossilized bones have shown evidence of abnormalities, such as asymmetrical bone growth, healed traumatic and repetitive stress fractures, arthritis, ossification (the development of bony-like material) of spinal ligaments, and the fusion of the animal’s spinal bones (or vertebrae).