Ankylo'sis

Ankylo'sis (Gr. ankylōsis, 'bending' or 'crooking;' ankylē, 'stiff-joint') is a term used in surgery to imply a stiffness in any joint. It is usually the result of disease, which destroys either the articular cartilages, leaving two bony surfaces opposed to each other, to become united by subsequent formation of bony or fibrous tissue, or thickens and shortens the natural fibrous tissues around the joint. Severe injury may also lead to a similar result. If the bond of union be osseous, the joint is perfectly rigid; if fibrous, it may allow a certain amount of motion. Some joints, especially the elbow, are very apt to become ankylosed; and in the knee or hip-joints, osseous ankylosis, with the limb in a proper position, is frequently the most favourable termination to disease, as the limb can then afford a rigid support for the trunk. Joints, stiff through a fibrous ankylosis, may be forcibly bent, and the bond of union ruptured, so as to restore mobility, or allow of their being placed in a convenient position. In some joints, especially the elbow, ankylosis may be remedied by excision of the joint. Ankylosis of the joints between the ribs and the vertebrae is common in advanced age; and there are some cases on record of universal ankylosis of all the joints. A case occurred in 1716 of a child only twenty-three months old with all its joints thus stiffened; and there are in various museums specimens of adult bodies in this condition.