Immobility of the joint due to the formation of bone, cartilaginous or fibrous tissues around the joint.

Ankylosis (from Greek ἀγκύλος (ankulos) 'bent, crooked') 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...