Comparative gross anatomy of the Heart in Human (Homo sapiens), Dog (Canis lupus familiaris), Horse (Equus caballus), and Ox (Bos taurus)

The heart is a vital muscular organ responsible for maintaining systemic and pulmonary circulation in vertebrates. While the basic structural plan is conserved across mammals, distinct interspecies variations exist in morphology, weight, orientation, and internal architecture, reflecting adaptations to body size, physiology, and lifestyle. This study is aimed to document and compare gross anatomical features of the heart in humans, dogs, horses, and oxen. Observations were based on available anatomical literature and dissection reports. Significant differences were noted in size, shape, cardiac axis orientation, valve morphology, and the presence of additional structures such as ossa cordis in oxen. These differences have clinical implications for veterinary and comparative cardiovascular medicine.