Tomographic and anatomical study of the orbit and nasolacrimal duct in capybaras (Hydrochoerus hydrochaeris—Linnaeus, 1766)

Abstract

The objective of this study was to describe the reference values of cranial measurements of capybaras, correlating the ocular orbit with the nasolacrimal duct. The documentation of its results can contribute to standardizing characteristics of anatomical normality and favouring the correct diagnosis and treatment of changes. The capybara carcasses, maintained by freezing, were distributed in two groups (G) designated GA (n = 12) adult animals (A) and GY (n = 13) for young animals (Y). All subjects underwent dacryocystography examination by computed tomography (CT) and cranial measurements. Descriptive analyses of cranial and nasolacrimal duct measurements and statistical analysis of the Pearson correlation with the variable weight were performed. In GA, there was no correlation between the nasolacrimal and cranial duct measurements. However, in the GY, a correlation was verified with facial length (r = .6233), facial width (r = .5771), cranial height (r = .6981), cranial length (r = .7116), total right length (r = .7517) and left length (r = .7999). Thus, in the young animals, cranial length measurements were strongly correlated with nasolacrimal duct lengths. However, this biological behaviour was not observed in adults, demonstrating stability in development. The capybara's ocular orbit was found to be circular and incomplete, with developed zygomatic process of the maxilla. CT dacryocystography is indicated to evaluate the nasolacrimal canal pathway in capybaras, emphasizing the importance of normal anatomical study to aid in treating animals affected by diseases.

Morphological evaluation of the orbit and peri-ocular glands of the African grasscutter (Thryonomys swinderianus)

“…The morphology of the rodent skull described in this study is similar to that of other rodents, such as the large South American rodent, capybara (Hydrochoerus hydrochaeris) (Hirota et al, 2018). The capybara, however, has a larger and heavier skull with a well-developed lacrimal bone.…”

Skull of Capybara (Hydrochoerus hydrochaeris) - Morphometric Parameters

“…Few studies on the head anatomy have been undertaken in the capybara such as estimation of the age of capybaras using some morphometric measurements of the skull [5], a tomographic and anatomical study of the orbit and nasolacrimal duct [8], an anatomorradiographic description of the teeth [10], and an anatomical description of the skull using radiography and 3D computed tomography [18]. There is scanty information on the morphometry of skull of capybara; therefore, the aim of this study was to describe the morphometric parameters of the capybara skull using normal morphometrical methods to contribute to gross anatomy of this Neotropical rodent.…”

Mandibular morphometry applied to local anaesthetic blockage in the capybara (Hydrochoerus hydrochaeris)

“…To these authors, the knowledge of the anatomy of the wildlife would facilitate the clinical‐surgical approach of the wildlife, which has been victim of trauma. The anatomy of the head region in the capybara has been studied in some aspects, such as, for example, an estimation of the age of capybaras using some morphometric measurements of the skull (Gorosábel et al, 2017), a tomographic and anatomical study of the orbit and nasolacrimal duct (Hirota et al, 2018), an anatomical description of the skull by radiographic and 3D computed tomography (Pereira et al, 2020) and a morphometric study of the skull (Ferrari et al, 2022).…”