Ankylosis


Ankylosis is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular structures outside the joint or of the tissues of the joint itself.
When the structures outside the joint are affected, the term "false ankylosis" has been used in contradistinction to "true ankylosis", in which the disease is within the joint. When inflammation has caused the joint-ends of the bones to be fused together, the ankylosis is termed osseous or complete and is an instance of synostosis. Excision of a completely ankylosed shoulder or elbow may restore free mobility and usefulness to the limb. "Ankylosis" is also used as an anatomical term, bones being said to ankylose when, from being originally distinct, they coalesce, or become so joined together that no motion can take place between them.
The term is from Greek ἀγκύλος, bent, crooked.

Causes

In 2014, Liliana Cernecca, a six-year-old girl at the time, was only able to open her mouth a couple millimeters after one of her jaw joints fused. She underwent surgery to correct her jaw ankylosis during which her jaw was operated on and unlocked.

Fossil record

Evidence for ankylosis found in the fossil record is studied by paleopathologists, specialists in ancient disease and injury. Ankylosis has been reported in dinosaur fossils from several species, including Allosaurus fragilis, Becklespinax altispinax, Poekilopleuron bucklandii, and Tyrannosaurus rex.