Though the Hippocratic text On the Heart has garnered significant attention in the twentieth and twenty-first centuries from classicists, physicians and historians of medicine alike, no commentary on this important work currently exists. There remain, however, central questions of interpretation concerning a number of important points: in particular, how the author understands the structure and functioning of the heart.

The significance of this text for the history of cardiovascular medicine can be found first in its position as being radically advanced in its portrayal of the inner structure of the heart when compared with any other Hippocratic text. At the same time, the text falls dramatically short of the discoveries of the Alexandrian researchers who studied during the Hellenistic period—that is, around the same period as this text’s likely composition. In addition, this work contains the first extant description of the valves of the heart, and its detailed descriptions of a cuspid valve and the chordae tendineae have led several scholars to imagine that this text even contains evidence of either a systematic dissection of an animal heart or—what seems impossible outside of Alexandria, Egypt at that time—evidence of the dissection of a human heart.

This article intends to provide a full commentary on the text by consolidating, and in some cases correcting, previous interpretive attempts to understand an often referenced, and at times misinterpreted, ancient medical treatise.