International Rhinologic Society Rhinology 0300-0729 2026 08 11 Mucus transport in the olfactory cleft is significantly slower than in the nasal respiratory mucosa EN A.K. Hernandez Smell and Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany AND Department of Otolaryngology - Head and Neck Surgery, College of Medicine and Philippine General Hospital, University of the Philippines - Manila, Manila, Philippines AND Department of Otolaryngology – Head and Neck Surgery, Asian Hospital and Medical Center, Muntinlupa, Philippines S. Biguerdi Smell and Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany K. Schindowski Institute for Applied Biotechnology, Biberach University of Applied Science, Biberach an der Riss, Germany T. Hummel Smell and Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany Letter 3495 10.4193/Rhin26.082 Intranasal mucociliary transport has been conventionally described as moving, essentially, in an anterior-to-posterior direction along the ciliated respiratory mucosa (RM). This mechanism is essential for clearing inhaled particles and pathogens and may be impaired in individuals with certain genetic conditions or infections.