Gross anatomy and morphometric evaluation of the canine lacrimal and third eyelid glands.

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. PROCEDURES: 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.

Ophthalmic diagnostic tests, orbital anatomy, and adnexal histology of the broad-snouted caiman (Caiman latirostris).

PURPOSE: The aim of this study was to establish normal ophthalmic parameters for selected diagnostic tests, and to describe the orbital anatomy and adnexal histology of the broad-snouted caiman. METHOD: A total of 35 Caiman latirostris that were free of obvious ocular diseases were used to measure the parameters in this investigation. Ages ranged from 5 to 15 years. Ophthalmic diagnostic tests were conducted, including evaluation of tear production with Schirmer Tear test-1 (STT1), culture of the conjunctival bacterial flora, applanation tonometry, conjunctival cytology, nictiating membrane incursion frequency test (NMIFT), endodontic absorbent paper point tear test (EAPPTT), palpebral fissure length measurement (PFL) and B-mode ultrasonography. Adnexal histology and skull samples were studied. RESULTS: Mean (±SD) STT1 was 3.4 ± 3.6 mm/min (95% confidence interval of 2.01-4.78 mm/min), intraocular pressure (IOP) was 12.9 ± 6.2 mmHg, NMIFT was 6.0 ± 3.5, EAPPTT was 17.1 ± 2.5 mm/min, PFL was 28.9 ± 3.0 mm, anterior chamber depth was 3.1 ± 0.3 mm, lens axial length was 8.4 ± 0.6 mm, vitreous chamber depth was 7.9 ± 0.7 mm and axial globe length was 19.9 ± 1.3 mm. For all animals evaluated, Bacillus sp., Diphteroids and Staphylococcus sp. were predominant.

Estudo retrospectivo de 71 casos de protrusão da glândula da terceira pálpebra (2009-2013) / Retrospective study of 71 cases of prolapsed third eyelid gland (2009-2013) / Análisis retrospectivo de 71 casos de prolapsos de glándula del tercer párpado (2009-2013)

Objetivou-se com esse estudo avaliar a incidência de protrusão da glândula da terceira pálpebra e correlacionar as características de raça e sexo com a lateralidade da alteração. Para isso, foram analisadas 3.151 fichas clínicas atendidas setor de oftalmologia veterinária da Universidade Estadual de São Paulo (UNESP) no período de 2009 a 2013, avaliando-se dados de incidência e lateralidade da afecção, além de idade, sexo e raça dos animais acometidos. Realizou-se a análise estatística de frequência e calculou-se o coeficiente de correlação de Spearman, considerando o nível de significância de 5%. Foram diagnosticados, no total, 71 casos de protrusão da glândula da terceira pálpebra em cães, correspondendo a 2,43% (71/2.916) da casuística de atendimento oftalmológico nesta espécie, porém não foi observado nenhum caso em gatos. Obteve-se uma maior frequência (58%, 41/71) em cães com idade inferior a 12 meses, sendo as raças mais acometidas: Lhasa Apso (24%, 17/71), Sem Raça Definida (20%, 14/71) e Beagle (14%, 10/71). Em 72% (44/71) dos casos a afecção se manifestou unilateral e 55% (39/71) dos animais eram fêmeas. Não houve correlação entre o sexo e a raça com a lateralidade da protrusão (p > 0,05). Com base no levantamento de dados realizados nesta instituição, conclui-se que a incidência da afecção é baixa em cães e rara em gatos, além de que não há influência do sexo e da raça com relação ao lado acometido pela alteração..

This paper aims to analyze the incidence of prolapsed third eyelid gland and correlate the breed and gender characteristics to the laterality of the alteration. In order to do this, three thousand one hundred and fifty-one (3151) medical records were analyzed at the Department of veterinary ophthalmology from the State University of São Paulo (UNESP) from 2009 to 2013, considering data such as the incidence and laterality of the disease, as well as age, gender and breed of affected animals. A frequency statistical analysis was performed and the Spearman correlation coefficient was calculated by taking the significance level of 5%. The prolapse of the third eyelid gland was diagnosed in 71 cases in dogs, which corresponds to 2.43% (71/2916) of the cases cared for in the ophthalmological assistance in this specie; however, no cases were observed in cats. Dogs younger than 12 months of age presented a higher frequency, (58%, 41/71). The breeds most affected were Lhasa Apso (24%, 17/71); Mongrel (20%, 14/71); and Beagle (14%, 10/71). The prolapse was unilateral in 72% (44/71) of the cases, and 55% (39/71) of the animals were female. There was no significant relation of gender and breed with the laterality of the prolapsed gland (p > 0.05). Therefore, it can be concluded that the incidence of the alteration is low in dogs and rare in cats, as well as no influence being related to gender and breed to the side affected by the alteration...

El objetivo de esta investigación ha sido evaluar la incidencia del prolapso de la glándula del tercer parpado y correlacionar las características de raza y sexo con la lateralidad de la alteración. Para tanto fueron analizadas 3151 fichas clínicas atendidas en el sector de oftalmología veterinaria de la Universidade Estadual de São Paulo (UNESP) entre 2009 y 2013, considerando datos de incidencia y lateralidad de la afección, además de edad, sexo y raza de los animales enfermos. Se realizó el análisis estadístico de frecuencia y fue calculado el coeficiente de correlación de Spearman, considerando el nível de significancia de 5%. Se ha diagnosticado 71 casos de prolapso de la glándula del tercer parpado en caninos, correspondiendo a 2,43% (71/2916) de la casuística del atendimiento oftalmológico en esta especie, sin embargo no se ha observado ningún caso en gatos. Hubo una frecuencia más grande (58%, 41/71) en perros con edad inferior a 12 meses, teniendo en cuenta que las razas que más presentaron este problema fueron Lhasa Apso (24%, 17/71), Sin raza definida (20%, 14/71) y Beagle (14%, 10/71). En 72% (44/71) de los casos, la afección se manifestó unilateral y 55% (39/71) de los animales eran hembras. No hubo correlación significativa entre el sexo y la raza con la lateralidad del prolapso (p > 0,05). Con base en el alzamiento de datos realizados en esta institución, se ha concluido que la incidencia de la afección es baja en perros y rara en gatos, además de no haber influencia del sexo y de la raza con relación al lado tomado por la alteración...

Periocular anterior adnexal anatomy and clinical adnexal examination of the adult Asian elephant (Elephas maximus).

Formalin preserved ocular-associated anterior adnexa tissues from five necropsied Asian elephants (Elephas maximus) were dissected with attention to the palpebrae, conjunctiva, nictitating membranes, nasolacrimal ducts, and periocular glandular tissues. Gross and histologic examination revealed that lacrimal and tarsal glands were not present. Evidence of the lacrimal drainage apparatus, including lacrimal punctae or any remnant of lacrimal sacs, was also absent. In contrast, well-developed sebaceous glands associated with accessory hairs along the palpebrae were exceptionally abundant. Mixed-secreting accessory lacrimal glands were noted in the deep stroma posterior to the tarsus of both palpebrae and the gland of the nictitating membrane. Apparently, the Asian elephant has developed a novel tear system in the absence of lacrimal and tarsal (meibomian) glands. Clinical examinations and bacterial cultures of the visible periocular tissues were performed on eight living adult Asian elephants to confirm the postmortem anatomic findings and provide guidance to the clinician during examination of the elephant conjunctiva.

Is it or isn't it? A reexamination of the anterior orbital glands of the fat-tailed Dunnart Sminthopsis Crassicaudata (Dasyuridae: Marsupiala) and a reevaluation of definitions for the Harderian gland.

The anterior orbital glands of tetrapods, which include the Harderian and nictitans glands, can usually be differentiated either anatomically (nictitans gland is more anterior) or histochemically (Harderian gland secretes lipids). However, conflicting statements exist in the literature about the presence and identity of these glands. Two previous studies on Sminthopsis crassicaudata (Dasyuridae: Marsupiala) either failed to note any anterior ocular glands or used no histochemical analyses. This study reexamined the structure of the anterior orbital glands of S. crassicaudata. Histological, histochemical, and ultrastructural examination revealed three glandular units: two of which are located superficially in the nictitating membrane, the third lying deeper in the connective tissue. The ducts of these three glandular units all open onto the corneal aspect of the nictitating membrane. These cells contain mainly serous granules with sparse intracellular lipid droplets. The nomenclature of these structures depends upon the definition used. According to the anatomical definition, S. crassicaudata has two glands: anteriorly the nictitans and posteriorly the Harderian gland. In contrast, if the histochemical definition is used, there is only one gland, but its precise identity cannot be confirmed until the role of the lipid droplets is established. Moreover, the histochemical definition poses additional problems with respect to the mechanism of secretion, multiple secretions, and glandular plasticity. Finally, the unitary definition identifies one deeply subdivided gland with an anterior and a posterior lobe in S. crassicaudata. This last definition is broad enough to accommodate a wide level of anatomical variation in the anterior ocular glands of tetrapods.

Morphology of deep gland of the third eyelid in pig foetuses.

The morphological and histological examinations of the deep gland of the third eyelid were carried out on pig foetuses coming from the 35th, 50th, 63rd, 94th and 112th day of gestation. The morphological examinations were conducted using the method of macroscopic preparation with a forehead magnifying glass and binocular (magnification 1.5-5.0x). In order to make anatomical elements more visible, 60-80% absolute alcohol and 0.5-4% acetic acid solution were used for the examinations. For the histological examinations, the whole eyeball with developing accessory organs was collected from the pig foetuses on the 35th day of gestation. On the 50th, 63rd, 94th and 112th day of gestation only the deep gland of the third eyelid was collected. Staining with haematoxylin-eosin and Azan method was performed. It was found during the examinations that the process of the formation of the deep gland of the third eyelid starts on the 35th day of gestation. On the 50th day of gestation, the gland cells are evenly distributed in the connective tissue stroma. On the 63rd day of gestation, the connective tissue divides the gland parenchyma into indistinct lobes composed of 6-15 lobules. On the 94th day of gestation, the gland lobes become visible; the efferent ducts are situated in the central part of the lobe. On the 112th day of gestation, the lobes are composed of a high number of lobules composed of two kinds of excretory ducts. The first type of the excretory ducts is lined with the simple cuboid epithelium whose nuclei are situated at the base of the cell. The other type of the excretory ducts is lined with the simple cuboid epithelium whose nuclei are round and arranged less or more peripherally.

Morphology of the third eyelid and superficial gland of the third eyelid on pig fetuses.

The morphological and histological examinations of the third eyelid and superficial gland of the third eyelid were conducted in pig fetuses coming from the 20th, 24th, 27th, 30th, 35th, 50th, 63rd, 94th and 112th day of gestation. The morphological examinations were carried out by applying the method of macroscopic preparation with a forehead magnifying glass and binocular (magnification 1.5-5.0x). In order to make anatomical elements more visible, 60-80% absolute alcohol and 0.5-4% acetic acid solution were used for the examinations. On the 20th, 24th, 27th and 30th day of gestation, the whole fetuses were collected for the histological examinations. The whole eyeball with developing accessory organs was collected from the pig fetuses on the 35th day of gestation. On the 50th, 63rd, 94th and 112th day of gestation, only the superficial gland with the third eyelid was collected. Staining with haematoxylin-eosin (H-E) and Azan method was performed. On the 20th, 24th, 27th and 30th day of gestation, the primordia of the glandular epithelium were not found in the examined material. The process of the third eyelid and superficial gland formation starts on the 35th day of gestation. On the 50th and 63rd day of gestation, the gland surrounding the cartilage of the third eyelid is composed of the high amount of loose connective tissue and gland cells which give rise to excretory segments. On the 94th day of gestation, the gland lobes become visible, the efferent ducts form. On the 112th day, the cartilage of the third eyelid assumes the appearance of the mature hyaline cartilage. The excretory segments are composed of simple cuboid epithelium with a large, round nucleus arranged less or more peripherally. Their number increases 2- or even 3-fold at the end of gestation.

Microalterations in the third eyelid gland of dogs with keratoconjunctivits sicca secondary to distemper

Keratoconjunctivitis sicca is characterized by qualitative or quantitative abnormalities in the aqueous component of the tear film and is frequent in dogs with distemper. Twenty-eight third eyelid glands of end-stage dogs that died from distemper were analyzed by light microscopy. Keratoconjunctivitis sicca was diagnosed based on ophthalmic findings regarding alterations in the ocular surface and by the Schirmer tear test. The excised glands were fixed in 10 percent buffered formalin and processed for embedding in paraffin. The blocks were cut into 4µm sections and the sections were stained with hematoxylin-eosin and Masson's trichrome. Analysis revealed tubuloacinar gland atrophy, thickening of connective tissue, and mild to intense inflammatory exudation mainly characterized by the presence of plasma cells and histiocytes and by compensatory hypertrophy of some glands. The glandular lumen was hypertrophied and contained shedded epithelial cells, polymorphonuclear cells and red blood cells, in addition to mucus.

Analisaram-se, à microscopia óptica, 28 glândulas da terceira pálpebra de cães, que morreram com cinomose. O diagnóstico de ceratoconjuntivite seca baseou-se nas alterações da superfície ocular e no teste da lágrima de Schirmer. A histologia, visibilizaram-se atrofia tubuloacina, espessamento do tecido conjuntivo e exudação inflamatória de leve a intensa com presença de plasmócitos, de histiócitos e por hipertrofia compensatória de algumas glândulas. O lume das glândulas encontrava-se hipertrofiado contendo células epiteliais descamadas, polimorfonucleares e hemácias, além de muco.

Normal anatomical and histochemical characteristics of the lacrimal glands in the American bison and cattle.

Dorsal lacrimal glands, superior glands of the third eyelid and Harderian glands (deep gland of the third eyelid) from 19 bison and 18 cattle free of apparent ocular disease were examined to compare the normal anatomical properties of these glands. All glands were characterized and measured (length and width). The gross anatomy of the dorsal lacrimal glands was similar, with the exception of a bipartite gland in cattle. The bison's superior gland of the third eyelid and Harderian gland was longer as compared with cattle. A subset of the bison and cattle samples (five bison and five cattle) was sectioned for histological and histochemical analysis. The histology of the dorsal lacrimal and superior gland of the third eyelid revealed tubuloalveolar cells with basophilic vacuolated cytoplasm in bison and eosinophilic granular cytoplasm in cattle. The Harderian glands consisted of a tubuloalveolar anterior part combined with large lumens acini lined with cuboidal epithelium in the posterior part; the posterior part of the bison Harderian gland was more predominant than in cattle samples. Mucosubstance histochemistry revealed acidic and neutral glycoproteins with similar staining patterns in all glands of both species.

[Morphology and structure of the nictitating membrane cartilage in mammals]. / Morphologie et structure du cartilage de la membrane nictitante des Mammifères.

In 30 species of Mammals of varying body size (from rat to elephant), the form, dimensions and structure of the cartilage of the third eyelid were studied. The cartilage is a thin lamina concave in its corneal side, usually elongated in the oro-aboral direction. In the most species studied the outline of the cartilage may be inscribed in a triangle with a oral base, a dorsal margin, a ventral margin and an aboral apex. A study of stained sections revealed, in more than half of species, the presence of elastic fibres in the aboral part of cartilage; these fibres are particularly numerous, but non uniformly distributed, in the Equidae, lion and Suidae.

The cartilage of the third eyelid: a comparative macroscopical and histological study in domestic animals.

The purpose of this comparative study was to evaluate morphological differences between the cartilages of the third eyelid in dogs, cats, pigs, cows, small ruminants and horses. For that reason a total of 83 third eyelids were investigated. By the aid of a modified maceration technique, the three-dimensional form of the cartilage could be demonstrated for the first time. Generally, the cartilage consists of a long narrow appendix which is followed by a variable crossbar. In dogs the appendix is cone shaped in the basal end and extends to form a triangular plate. The former is crescent-like in shape and has a marked bulge. The cartilage of the cat consists of an appendix which is enlarged in the proximal end as compared to the dog. The crossbar resembles a reverse s-form with ends tapering off to a point. In contrast pig and cow cartilage possess a typical anchorform whereas the cartilage of small ruminants starts with a thin rod which extends in a slightly curved form ending in an oval plate. The crossbar is crescent-like in these animals. In the horse the base of the cartilage is surrounded by a massive fatty tissue and the crossbar has a characteristic hook-form. Moreover, there are significant differences in regard to the quality of the cartilage, especially concerning the presence and distribution of elastic fibres. In cats and horses the elastic fibres of the adjacent connective tissue penetrate the perichondrium. Additionally, the centre of the cartilage shows a very dense network consisting of fine elastic fibres. In dogs, pigs, cows and small ruminants the cartilage consists of hyaline quality and only in the neighbouring connective tissue are some elastic fibres detectable.

An additional bone in the sclera of the eyes of owls and the common potoo (Nictibius griseus) and its role in the contraction of the nictitating membrane.

Morphometric, anatomical and histological examinations were made in 10 species of owls of the families Tytonidae and Strigidae and compared with the eyes of other species of nocturnal birds including common potoo (Nictibiidae) and three species of nightjars (Caprimulgidae) and two diurnal species: the roadside hawk (Accipitridae) and the domestic duck (Anatidae). In owls and the common potoo the nictitating membrane is situated on the dorsal edge of the eye. In these birds, the scleral ring bears an additional, previously undescribed bone of various forms and dimensions (1.4-6.8 mm of length and 0.8-3.3 mm of width), located on the trajectory of the tendon of the pyramidal muscle which is attached to the nictitating membrane. This bone has a groove that encloses the tendon of the pyramidal muscle, preventing it from separating from the sclera during contraction, as well as diverting the trajectory of the tendon to impede it from projecting itself over the cornea. In the ferruginous pygmy owl, Nacunda nighthawk, Pauraque, scissor-tailed nightjar, roadside hawk and domestic duck the additional bone was not seen. Based on the morphofunctional characteristics of the bone, we suggest that this bone should be named the scleral sesamoid bone.

Morphologic study of the musculature of the third eyelid in the cat (Felis catus).

The presence of smooth and striated muscles associated with protrusion or retraction of the feline third eyelid was investigated histologically in eight cats. Nine smooth muscle strands extending into the third eyelid are described and illustrated. No striated muscle fibers extending into or within the third eyelid were observed.

Anatomia funcional da membrana nictitante de Gallus gallus domesticus / Funcional anatomy of nictitating membrane of the Gallus gallus domesticus

Estudo da anatomia da membrana nictitante, sua fixaçäo, seu aparelho muscular, sua dinâmica, histologia e arquitetura. Para isso foram utilizadas 30 aves. As contraçöes dos músculos piramidal nictitante e quadrado nictitante possibilitam às aves distenderem a membrana nictitante rapidamente e retrairem-na passivamente devido a sua estrutura elástica, o que foi observado através de fotogramas. A velocidade de retraçäo e expansäo em ave de um ano e meio, foi, em 70% dos casos, de 1/6 segundos e, em 30% dos casos, 1/9 segundos. Já nas aves de 90 dias, o tempo foi de 1/8 segundos em 100% dos movimentos registrados. O estudo histológico através de microscopia óptica convencional e de luz polarizada, demonstrou a relaçäo entre a arquitetura dos elementos constitutivos da membrana nictitante e sua anatomia funcional. Constatamos que a membrana nictitante apresenta dois sistemas de disposiçäo das fibras elásticas (com predomínio das elásticas propriamente ditas), sendo um na periferia, denso, formando uma faixa e outro na regiäo central formando uma rede. As fibras colágenas têm disposiçäo predominante sub-endotelial, existindo em todo estroma da membrana e condensando-se na margem livre e no ponto de fixaçäo

The skin of the giraffe.

The skin of the giraffe has the same general histological structure as that of other mammals, but there are notable features. The skin is heavily pigmented with the epidermis, pilary canals, and the outer cell layer of the apocrine duct richly melanized. Furthermore, melanotic dendritic cells are frequently found in the sebaceous glands, the entire length of the external root sheath, and the secretory tubules of the apocrine glands. The thick skin has a papillary dermis that extends to just beneath the secretory coils of the apocrine glands and bulbs of hair follicles and an equally thick reticular layer below these structures. The hair follicles do not grow in clusters, and with some regional variations, have associated sebaceous glands, apocrine glands, and arrectores pilorum muscles. Only the large hairs have a prominent medulla. In such specialized regions as the eyelids, nose, and lips, the apocrine glands are surrounded by cholinesterase-reactive nerves but the glands on the general body surface are not. The only specialized nerve receptors are hair follicle end organs found on every hair of the eyelids, nose, and lips, but only rarely elsewhere.