Anchylosis is that condition of a joint in which the bones forming it are united in such a way as to restrict or altogether prevent their natural movement taking place. The various means by which this is effected has given rise to a division of anchylosis into true and false. True anchylosis results when, as a consequence of disease, the two ends of the bones within the capsular membrane become united. False anchylosis is induced when inflammatory products surround and enclose the joint, and become callous or ossified, or in other ways fix the ends of the bones and prevent their movement.

Anchylosis may be complete or incomplete. In the former the union is effected by ossific new growth between or around the ends of the bones forming the joint, and the movement is altogether arrested. In the latter the bones are bound together by fibrous or fibro-cartilaginous tissue, which allows a limited degree of movement to take place in the joint. The uniting medium in this case may sooner or later become converted into bone, by which complete anchylosis is effected. The incomplete form of the disease therefore represents a stage in the development of the complete; in other words, when the fibrous tissue existing in the one becomes ossified, it is converted into the other.

Causes

Anchylosis is the result of inflammation affecting the joint or parts about it. External violence, in the form of blows, wounds, sprains, and other injuries, is the exciting cause.

In the matter of treatment, but little can be done to render an animal of service for anything but slow work, unless for breeding purposes.

To break down the morbid development uniting the bones by physical force is a practice sometimes adopted in man, but the ultimate success of such an operation depends upon the complete control and obedience of the patient, which cannot be obtained in the horse.