Animal cerone
Star vault in the Toruń Cathedral (formerly Thorn ). A = belt rib, B = cross rib, C = Tierceron, D = keystone , E = Lierne rib, F = arcade arch
As Tierceron be in the Gothic architecture small side rip 2nd degree a vault called. They lead from the corner of the yoke not to the keystone , but to the apex or cross rib; they no longer have a load-bearing but only a decorative function.
Even shorter connecting ribs without lateral support and without a connection to the keystone are called Lierne ribs.