Anatomy of the nasolacrimal duct in Persian cats determined by computed tomographic dacryocystography.

Abstract

This study sought to describe the anatomical characteristics of the nasolacrimal duct of Persian cats as observed by computed tomographic dacryocystography. Ten cats weighing 3-6kg (three live cats and seven cadaveric specimens). The animals were submitted to bilateral computed tomographic dacryocystography, totaling 20 nasolacrimal ducts. Dorsal, sagittal, and transverse planes were studied. Two additional skulls were also dissected following latex injection into the nasolacrimal duct. The length and width of the nasolacrimal duct and lacrimal canaliculi, and the distance between the nasolacrimal duct and the root of the upper canine tooth at the point of closest proximity were measured. The nasolacrimal duct followed a convoluted course, particularly in the middle and rostral portions. Duct stenosis (width reduction equal to or >75%) and dilations (width increase equal to or >50%) were also detected, particularly in the rostral portion. Nasolacrimal duct length and width ranged from 1.3 to 1.5cm and 1.5 to 2.3mm, respectively. Mean lacrimal canaliculus length and width corresponded to 3.1mm and 0.4mm, respectively. Mean distance from the nasolacrimal duct to the canine tooth was 2.4mm. The root of this tooth interfered with the course of the nasolacrimal duct. This study provided anatomical information for clinical assessment of the nasolacrimal drainage system in Persian cats.