Morphometry of the heart of greater rhea (Rhea americana americana, Linnaeus, 1758)

Heart diseases in birds are frequent and generate significant production disorders. Morphometry is a valuable tool to provide fundamental information about heart conditions. Few studies have addressed morphological aspects of the heart of ratite birds, such as the Greater rhea. The present study aimed to analyse rhea heart morphometry, comparing young and adult subjects, in order to provide relevant information for the diagnosis of heart disease in this species. Hearts of young (n = 10) and adult (n = 10) female rheas were used in this research. Heart length and width and sternum length were measured using a caliper. Heart length and width and sternum length in adults were approximately three times greater than in young individuals. The left ventricular wall (LVW) was thicker than the right ventricular wall (RVW) at all ages, and the RVW was thicker in adults when compared to young subjects. The basal and middle RVW regions thicken with advancing age, and the thickness of the interventricular septum (ISW) occupies an intermediate position between the LVW and RVW. In general, an increase in rhea heart thickness and size relative to age is observed. The morphometric variations between young and adult rhea hearts observed in the present study may serve as a comparative subsidy for the diagnosis of cardiac abnormalities observed in this species.

Automated summary

This study focused on analyzing the morphometry of the Greater rhea heart, showing that adult individuals have hearts approximately three times larger than young ones, with the left ventricular wall thicker than the right ventricular wall overall. Additionally, it was observed that the right ventricular wall thickness increases with age, especially in the basal and middle regions. The morphometric variations between young and adult rhea hearts identified in this study could be used as a comparative tool for diagnosing cardiac abnormalities in this species.