Fig. 23. Diagram of the valves and sinuses of the nasolacrimal passages. 1 = Maier's sinus; 2 = Rosenmüller's valve; 3 = Arlt's sinus; 4 = Kraus's or Béraud's valve; 5 = spiral valve of Hyrtl; 6 = Taillefer's valve; 7 = Hasner's valve.