External macroscopic anatomy of the Bradypus variegatus heart

Abstract

The sloth is known for its slow movements and arboreal habits. Most parts of its anatomy need yet to be unveiled, in order to understand the peculiarities that justify its behavior. In this sense, an investigation of the external characteristics of the heart of the three-toed sloth, Bradypus variegatus, was carried out to indicate the shape, the faces, the dimensions, the topography, and the coating of this organ. For this purpose, fifteen corpses destined for dissection and four healthy specimens were used to carry out thorax digital x-ray. Based on the obtained results, it was noticed that the heart of the species in question presents conical shape, situated obliquely in the mediastinum, is displaced to the left and has latero-lateral slight flattening. Among the animals, discrepancies were found in the organ skeletopy, which presents the tapered apex and the base, in which the large vessels can be observed, whose arrangements also proved to be variables. The heart presents faces (right and left), margins (cranial and caudal) and is surrounded by the pericardium, which gives off two ligaments, sternopericardial and phrenico pericardial. Its size is proportional to the age and length of the individual, with measurements, in general, slightly larger in males.