In the lower two the ligament sometimes completely obliterates the cavity, so as to convert the articulation into an amphiarthrosis.    From Wordnik.com.  [III. Syndesmology. 1F. Sternocostal Articulations] Reference

These hurts are not often of a very serious character, though the union is never so solid and complete as in other fractures, the callus being usually imperfect and of a fibrous character, with an amphiarthrosis formation.    From Wordnik.com.  [Special Report on Diseases of the Horse] Reference