Cusp ridges are ridges that radiate from cusp tips. The ascendant does not coincide with the cusp for the 1st house. Premolars are primitive, with one primary cusp and various secondary cusps. This is the buccal cusp for mandibular teeth and the palatal cusp for maxillary teeth. The apical cusp is the primitive protoconid. There is one large cusp on the buccal side of the tooth. The model of the structural fracture mechanics is similar to the cusp catastrophe behavior. Peter Lawrence described Jonny as a "hero in training" on the cusp of adulthood. The right coronary artery (RCA) originates within the right cusp of the aortic valve. These shapes often have cusp singularities. Some sources also advocate they be named as a left, right and posterior cusp. Twelve is the smallest weight for which a cusp form exists. It can also be defined as an epicycloid having a single cusp. The teeth are moderately large with a single, narrow cusp. The cause of talon cusp is unknown.