title: Anatomical relationship of Horner's muscle origin and posterior lacrimal crest.
abstract: OBJECTIVE
  This study was designed to examine the distance from the posterior lacrimal crest to the posterior margin of the Horner's muscle origin (the PLC-HMO distance), considering their complex anatomical relationship.
  
  
  METHODS
  Eight macroscopic specimens from 8 Japanese cadavers and 7 microscopic specimens from 7 Japanese cadavers, fixed in 10% buffered formalin, were analyzed. Macroscopically, the PLC-HMO distance was measured at 2 mm superior to the most posterior point of the muscle origin (Group A), directly at the most posterior point (Group B) and 2 mm inferior to the most posterior point (Group C). Microscopically, the PLC-HMO distance was measured in axial sections at 1 mm above the upper eyelid margin (Group 1), 1 mm below the lower eyelid margin (Group 2), and 3 mm below the lower eyelid margin (Group 3).
  
  
  RESULTS
  In the macroscopic study, the average PLC-HMO distance was 2.94, 2.57, and 2.05 mm for Groups A, B and C, respectively. The distance for Group C was significantly smaller than that of Group A (p = 0.006). In the microscopic study, the average PLC-HMO distance was 3.62, 3.74, and 3.14 mm for Groups 1, 2 and 3, respectively (no significant difference).
  
  
  CONCLUSIONS
  The PLC-HMO distance was approximately 2-4 mm with some specimens showing a smaller distance inferiorly.
authors.affiliation: Department of Ophthalmology, Aichi Medical University, Nagakute, Aichi, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kakizaki
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ichinose
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Hyera
authors.initials: H
authors.lastname: Kang
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ikeda
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
mesh_terms: D000369:Aged, 80 and over; D044466:Asian People; D002102:Cadaver; D005143:Eyelids / Q000033:anatomy & histology*; D005152:Facial Muscles / Q000033:anatomy & histology; D006801:Humans; D007564:Japan; D007765:Lacrimal Apparatus / Q000033:anatomy & histology*; D009801:Oculomotor Muscles / Q000033:anatomy & histology*