Anomalous tubercle

The anomalous tubercle (cusp of Carabelli, Carabelli's tubercle, or tuberculum anomalum of Georg Carabelli) is a small additional cusp at the mesiopalatal line angle of maxillary first molars. This extra cusp is usually found on the first molar, and becomes progressively less likely in the second, third molars. This cusp is entirely absent in some individuals and present in others in a variety of forms. In some cases, Carabelli's cusp may rival the main cusps in size. Other related forms include ridges, pits, or furrows.