Anatomical relationship of Horner's muscle origin and posterior lacrimal crest.

PURPOSE

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.