Abstract
1. Pathological changes occurred in the manubrio-sternal joint in 72 per cent of a series of sixty-one cases of ankylosing spondylitis.
2. In all the twenty-one patients over the age of thirty-five years the joint was undergoing a process of fusion that was found in only seven of sixty healthy persons in the same age group.
3. In the age groups twenty-five to forty-four, thirty-five out of forty-three patients with ankylosing spondylitis showed abnormality that was noted in but three of the forty healthy controls.
4. The changes in the manubrio-sternal joint are similar to those which occur in the sacro-iliac joint.
5. The accessibility of the manubrio-sternal joint makes it a convenient source of pathological material for the further histological study of the disease.
