Elastic nature of the lacrimal canalicular wall

To examine the elastic nature of the lacrimal canalicular wall.

Fifteen postmortem specimens of 11 Japanese individuals (8 right, 7 left; age range, 45-89 years at death) fixed in 10% buffered formalin were axially sliced parallel to the lower eyelid margin to include all 3 portions of the lacrimal canaliculi (intrasac, extrasac-extramuscular, and intramuscular portions). All specimens were stained with Elastica van Gieson. Microscopic photographs were taken and converted to white (elastic fibers) and black (the other tissues) images to measure the elastic fibers in an area in each portion.

Six specimens in 4 individuals (2 right, 4 left; age range, 62-87 years) included all 3 portions. The area of elastic fibers in the intrasac portion (mean area, 125.8±93.6 white dot) was not significantly different from that in the extrasac-extramuscular portion (p=0.637: mean area, 268.5±150.2 white dots) but was significantly smaller than the areas in the intramuscular portion (p<0.001: mean area, 796.3±278.1 white dots) and Horner's muscle fascia (p<0.001: mean area, 1052.8±250.1 white dots). The area of elastic fibers in the extrasac-extramuscular portion was also significantly smaller than areas in the intramuscular portion (p=0.001) and Horner's muscle fascia (p<0.001). There was no significant difference in the area between the intramuscular portion and Horner's muscle fascia (p=0.172).

The elastic nature of the lacrimal canalicular wall was different in areas with or without Horner's muscle envelope.