title: The orientation of the lacrimal fossa to the bony nasolacrimal canal:  an anatomical study.
abstract: OBJECTIVE
  To examine the relative positions of the lacrimal fossa (LF) and the bony nasolacrimal canal (BNLC) in relation to each other and a reference plane.
  
  
  METHODS
  Forty-two orbits and BNLCs from 21 Asian cadavers (9 men and 12 women; average age at death, 84.4 years; range, 70-99 years) had been fixed in 10% buffered formalin before use. After exposing the LF and the medial half of the BNLC, the authors measured the angles of the longitudinal axis of the LF and the BNLC relative to the aesthetic horizontal plane respectively. Based on these values, the relative orientation of the LF and the BNLC was determined and defined in terms of Δ BNLC-LF. A positive Δ BNLC-LF represents a nasolacrimal canal that descends posteriorly relative to the LF.
  
  
  RESULTS
  The mean LF, BNLC, and Δ BNLC-LF were 9.5°, 19.8°, and 10.3°, respectively. In 39 passages (92.9%), the Δ BNLC-LF was positive, representing a nasolacrimal canal that is more posteriorly oriented than the LF. In 3 passages (7.1%), the Δ BNLC-LF was equal to or less than 0°; 2 of them (4.8%) had a straight course and 1 passage (2.4%) had a negative value.
  
  
  CONCLUSIONS
  In most patients, the BNLC is directed more posteriorly than the LF. This finding may help in preventing an inadvertent false passage during probing and intubation in patients with epiphora.
authors.affiliation: Department of Ophthalmology and Visual Science, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Juwan
authors.initials: J
authors.lastname: Park
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.forename: Ken
authors.initials: K
authors.lastname: Asamoto
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Iwaki
authors.forename: Dinesh
authors.initials: D
authors.lastname: Selva
authors.forename: Igal
authors.initials: I
authors.lastname: Leibovitch
authors.forename: Suk-Woo
authors.initials: SW
authors.lastname: Yang
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kakizaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002102:Cadaver; D005260:Female; D006801:Humans; D007765:Lacrimal Apparatus / Q000033:anatomy & histology*; D008297:Male; D009301:Nasolacrimal Duct / Q000033:anatomy & histology*; D009915:Orbit / Q000033:anatomy & histology*