Eponymous “valves” of the nasolacrimal drainage apparatus. II. Frequency of visualization on dacryocystography: “Valves” of the Nasolacrimal Drainage Apparatus

: Developmental remnants may follow segmental canalization of ectodermal epithelial cords forming the nasolacrimal drainage apparatus (NDA). This can result in false luminal "valves" along the path of the NDA, many of which have been named, but most have not been anatomically identified with consistency. By 1908, eight such "valves" were documented, those of: Foltz, Bochdalek, Rosenmuller, Huschke, Aubaret, Beraud or Krause, Taillefer, and Hasner or Cruveilhier or Bianchi. Digital subtraction dacryocystography (DS-DCG) is the highest spatial resolution imaging technique available to outline in vivo NDA anatomy, luminal profile, and pathology. We believe this is the first report of the conspicuousness and frequency of these "valves" on DS-DCG. We retrospectively analyzed routine DS-DCGs with normal findings for the presence and frequency of the eight NDA "valves." We examined 92 normal DS-DCGs on patients aged 14-82 years (71% female, 29% male). We observed "valves" most reliably in the inferior nasolacrimal duct: the inferior valve of Hasner (plica lacrimalis) was present in 98.9% of cases, and more superiorly, the valve of Taillefer (93.5%) and the valve of Krause (79.3%). Contrastingly, we infrequently identified the very superior "valves": Foltz or Bochdalek in 17.1%, Rosenmuller or Huschke in 46.4%, and Auberat in 40% of cases. Therefore, unlike the inferior NDA valves, these more superior "valves" were less consistently identified and are presumed to be simple mural mucosal irregularities rather than true structural valves. These findings will be useful in diagnostic interpretation of DS-DCGs and therapeutic planning for patients undergoing luminal procedures on the NDA. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc.