Pain! Pain! Pain! Dinosaurs also suffer from cervical spondylosis?

The huge dinosaur fossil skeletons in the museum always make people feel the magic of life. The once dominant overlords lived and multiplied on the vibrant land billions of years ago, how carefree they were. But in fact, dinosaurs, like humans, will grow old, get sick and die, and they will also suffer from illness.

In Lufeng City, Chuxiong Yi Autonomous Prefecture, Yunnan Province, a dinosaur fossil with cervical vertebrae hyperosteogeny was discovered. The discovery was published in the international academic journal "Polish Paleontological Journal", which attracted widespread attention. This is also the first time that bone hyperplasia has been found in a dinosaur fossil.

Page of the paper "Vertebral Fusion of Two Early Jurassic Sauropods from the Lufeng Formation, Yunnan" (Xing Lida et al.)

Patients with cervical spondylosis 190 million years ago

In 1938, paleontologists discovered the skeletal fossil of Lufengosaurus, a famous sauropod dinosaur that lived 190 million years ago, in Dachong Village, Jinshan Town, Lufeng City. The fossil had two deformed cervical vertebrae, which made paleontologists wonder: "Where did this deformity come from? Was it caused by a bite from another dinosaur? Or was it caused by disease?"

In order to find out the reason, the researchers conducted further observations and comparisons. No obvious infection holes or changes in bone density were found around the cervical vertebrae of the fossilized vertebrae, and no tooth marks were found on the surface of each vertebra. Therefore, they first ruled out the possibility of being bitten by other dinosaurs and inferred that this dinosaur was more likely to suffer from cervical spondylosis.

To find out what disease the dinosaurs suffered from, paleontologists continue to conduct in-depth tests.

Lu Fenglong's cervical spondylosis was caused by bone hyperplasia

Lufengosaurus is a type of giant sauropod dinosaur with a thin and long neck, which is about 88% of the length of the back. In order to reduce the burden of the "long neck", the long tail behind it can keep the body balanced when walking. However, when this balance is broken, cervical problems will arise.

Figure: Normal cervical vertebrae

Simply put, bone hyperplasia in humans manifests itself as the muscles, ligaments and other tissues around the spine and joints of the human body undergo degenerative changes as age continues to increase, causing the balance of the spine and joints to be destroyed, and the spine and joints to become unstable. In order to adapt to these changes, the human body will grow bone spurs to increase the surface area of ​​the bones, thereby reducing the pressure per unit area of ​​the bones. Although the spine will be more stable at this time, the human body will also have bone hyperplasia. When bone hyperplasia occurs in the neck, the area around the neck is hard and cannot be turned flexibly, and it will also make a "clucking" sound. For this Xu's Lufengosaurus, its cervical spondylosis has reached a very serious stage. The hyperplastic bones of the 7th and 8th cervical vertebrae are firmly combined and difficult to distinguish from each other, so that they do not look as "clearly divided" as normal cervical vertebrae. This indicates that Xu's Lufengosaurus may suffer from illness for the rest of its life and find it difficult to use its long neck flexibly. Every time it raises and lowers its neck to eat plants and drink water, it is a huge torture.

Figure: Various views of the diseased vertebra

Figure: Rough surface of the posterior surface of the spinal nerve of the 7th cervical vertebra (A) and the 8th cervical vertebra (B)

According to Wang Tao, director of the Lufeng City Dinosaur Fossil Conservation and Research Center, when paleontologists first came into contact with these fossils, they did not immediately realize that they were caused by disease, but later analysis showed that they were all spondyloarthropathies, that is, bone hyperplasia. Although the diseased Lufengosaurs may have been affected in some way at the time, due to the large number of their tail and cervical vertebrae, the ossification did not seem to threaten their lives, and they probably lived in this condition for quite a long time.

It seems that bone hyperplasia is not a "disease exclusive to humans". Dinosaurs also suffered from the same bone diseases as modern humans. Understanding the characteristics of the same disease in different species will not only help humans further understand the origin and evolution of this ancient biological pathology, but also make us take a step further in the research of fighting the disease.