title: Evaluation of the canalicular entrance into the lacrimal sac: an anatomical study.
abstract: OBJECTIVE
  The purpose of this study was to investigate the prevalence of a common canalicular entrance in the lacrimal sac and to investigate the anatomy of the canalicular/lacrimal sac junction with direct visualization using a novel cadaveric dissection technique.
  
  
  METHODS
  Preserved cadavers were dissected to allow direct visualization of the canalicular entrance(s) to the lumen of the lacrimal sac. The prevalence of a common canaliculus and the anatomical variations of the canalicular/lacrimal sac mucosal fold of tissue were recorded.
  
  
  RESULTS
  One hundred twenty-four lacrimal systems (95 cadavers; 43 female, 52 male) were included in the study analysis. Overall, 123 lacrimal systems demonstrated a common canaliculus entering the lacrimal sac. Only one demonstrated 2 separate orifices (right orbit; male) in the sac (0.08%; 95% confidence interval, 0.1%-4.4%). Seventy-four lacrimal systems had some variation of a canalicular/lacrimal sac mucosal fold (59.7%). The remaining 50 (40.3%) had no visible canalicular/lacrimal sac mucosal fold.
  
  
  CONCLUSIONS
  This study provides direct anatomical evidence that the prevalence of separate canalicular orifices in the lacrimal sac is lower than previously reported (<1%). Additionally, the presence of a valve-like structure at the canalicular/lacrimal sac junction is common. These observations can potentially play a role in evaluating and treating lacrimal system pathology.
authors.affiliation: Department of Ophthalmology, Division of Ophthalmic Plastic and Reconstructive Surgery, New York University School of Medicine, New York, New York, USA. czoumalan@gmail.com
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Zoumalan
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Joseph
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Lelli
authors.forename: Kira L
authors.initials: KL
authors.lastname: Segal
authors.forename: Amanda
authors.initials: A
authors.lastname: Adeleye
authors.forename: Michael
authors.initials: M
authors.lastname: Kazim
authors.forename: Richard D
authors.initials: RD
authors.lastname: Lisman
mesh_terms: D005260:Female; D006801:Humans; D007765:Lacrimal Apparatus / Q000033:anatomy & histology*; D008297:Male; D009301:Nasolacrimal Duct / Q000033:anatomy & histology*