Abstract
Purpose:
The lacrimal gland (LG) and the third eyelid gland (TELG) are two intraorbital glands that secret the aqueous component of the tear film in dogs. Despite the central importance of these structures for maintaining ocular surface health, the anatomy and imaging of the glands remains understudied. We investigated the macroscopic, morphometric, CT, and MRI characteristics of the LG and TELG in normal dogs.
Methods:
Twenty-six dog heads were dissected to expose the LG and TELG. The length, width, thickness, and weight of both glands were measured. The relationships between the glands and adjacent ocular structures and blood and nerve supplies to the LG were photodocumented during the dissection. Fifty dogs were imaged (42 CT and 8 MRI), and the volume was calculated for the LGs and TELG.
Results:
The LG is a flat and oval shape with some morphological variations between dogs located on the dorsolateral aspect of the globe beneath the orbital ligament. The average length, width, and thickness (SD) of the LG were 18.4±3.5, 13.1±2.1, and 2.9±0.5 mm and of the TELG were 14.4±5.3, 10.5±2.9, and 3.2±0.5 mm, respectively. The mean weight (SD) of the LG and TELG were 315.7±103.3 and 263.3±56.3 mg and the volume measured by CT and MRI imaging were 0.14±0.1 and 0.1±0.1 cm3, respectively.
Conclusions:
The present study provides detailed normative anatomical and morphometric data for the LG and TELG. These data will be essential in evaluation of alterations induced by disease states as well as informing strategies for the local delivery of pharmacologic and cellular therapeutics.