title: Gross anatomy and morphometric evaluation of the canine lacrimal and third eyelid glands.
abstract: OBJECTIVE
  The lacrimal gland (LG) and the third eyelid gland (TELG) are two intraorbital glands that, in dogs, secrete the aqueous component of the tear film. Despite the central importance of these structures for maintaining ocular surface health, the gross anatomy of the glands remains understudied. We investigated the macroscopic morphometric characteristics of the LG and TELG in three different dog breeds.
  
  
  METHODS
  Twenty-six dog heads were dissected to expose the LG and TELG; the length, width, thickness, and weight of each were measured. During the dissections, the relationships between the glands and adjacent ocular structures and the blood and nerve supplies to the LG were photo-documented.
  
  
  RESULTS
  The LG had a flat and irregular shape with morphological variations among dogs. The LG was located on the dorsolateral aspect of the globe underneath the orbital ligament. The average length, width, and thickness (SEM) of the LG (mm) were 16.5 ± 0.7, 12.5 ± 0.4, and 2.7 ± 0.1 and of the TELG 10.5 ± 0.6, 11.0 ± 0.3, and 3.3 ± 0.1, respectively. The mean weights (SD) of the LG and TELG (mg) were 315.7 ± 21.1 and 263.3 ± 13.2, respectively. Beagles were observed to have significantly smaller LGs compared to pit bull terriers and pointer mixed-breed dogs.
  
  
  CONCLUSIONS
  The present study provides detailed normative anatomical and morphometric data for the LG and TELG. These data will aid researchers investigating alterations induced by disease states and should inform strategies for the local delivery of pharmacologic and cellular therapeutics.
authors.affiliation: Veterinary Surgical and Radiological Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Shin Ae
authors.initials: SA
authors.lastname: Park
authors.affiliation: Department of Anatomy, Physiology and Cell Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Ken T
authors.initials: KT
authors.lastname: Taylor
authors.affiliation: Veterinary Surgical and Radiological Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Allison L
authors.initials: AL
authors.lastname: Zwingenberger
authors.affiliation: Department of Pathology, Microbiology and Immunology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Reilly
authors.affiliation: Department of Anatomy, Physiology and Cell Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Chrisoula A
authors.initials: CA
authors.lastname: Toupadakis
authors.affiliation: Department of Anatomy and Cell Biology, Indiana University School of Medicine-South Bend, South Bend, IN 95616, USA.
authors.forename: Carl F
authors.initials: CF
authors.lastname: Marfurt
authors.affiliation: Veterinary Surgical and Radiological Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Good
authors.affiliation: Veterinary Surgical and Radiological Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.|Department of Ophthalmology & Vision Science, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Murphy
mesh_terms: D000818:Animals; D004285:Dogs / Q000033:anatomy & histology*; D005260:Female; D007765:Lacrimal Apparatus / Q000033:anatomy & histology*; D008297:Male; D009541:Nictitating Membrane / Q000033:anatomy & histology*
keywords: beagle; breed difference; dog; intraorbital location; nictitans gland; size