A 39-year-old man in the United States was found to have a rare “cardiac bone” during an autopsy following a fatal stabbing.The unusual finding-a boomerang-shaped structure within his heart-has sparked debate among medical experts about how common such formations might be in humans.

A Bone in the Heart? The Curious Case of the Os Cordis

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Published: November 21, 2023

  • The structure, called an os cordis, is a bony growth within the heart, typically seen in animals like cows and camels.
  • It was discovered during an autopsy of a 39-year-old man who died from a stab wound.
  • Researchers are debating whether this structure is truly rare in humans or simply frequently enough overlooked.

The man, who died after a fight where a stab wound punctured a vein in his lungs, also had an enlarged heart and moderate atherosclerotic coronary artery disease. But it was the unexpected revelation during the autopsy that has captured the attention of the medical community. Medical examiners noticed a lump near the atrioventricular node, the area coordinating electrical signals between the heart’s chambers. Slicing into the tissue revealed the “boomerang-shaped, bony structure,” roughly the size of a black bean, according to a case report.

What is the Os Cordis and Why is it Unusual?

The os cordis, meaning “heart bone” in Latin, isn’t entirely unknown to science. It’s commonly observed in nonhuman mammals, where it’s believed to provide support for the heart valves. However, its presence in humans is exceedingly rare.The structure was only recently described in primates, with a 2020 report detailing its presence in three out of 16 chimpanzee hearts examined. Interestingly, those chimps also showed signs of heart tissue scarring, leading researchers to speculate a link between tissue damage and the development of the bony structure.

In 2020, a similar structure, dubbed the “cardiac fulcrum,” was identified in seven humans by Dr.Jorge Trainini, a cardiac surgeon and professor at the National University of Avellaneda in Argentina. Trainini and his team proposed the fulcrum stabilizes heart muscles during pumping. They found the human fulcrum consisted of cartilage and tendon, unlike the bone found in cow hearts, but noted bone tissue was present in a 10-year-old’s heart-a heart explanted during a transplant due to cardiomyopathy. This led them to suggest the structure might become less bony with age.

Is the os cordis and cardiac fulcrum the same thing? While Trainini believes they are, the authors of the recent case report disagree, maintaining the structure they found in the 39-year-old man was distinct due to its bony composition.

Coudl These Structures Be More Common Than We Think?

Despite the disagreement, both groups arrive at a similar conclusion: the os cordis, or cardiac fulcrum, may be more prevalent in humans than currently recognized. The case report authors suggest the structure is frequently enough missed as standard autopsy procedures don’t routinely involve detailed dissection of the heart tissue. trainini even suggests that all humans likely possess a cardiac fulcrum, based on his investigations of approximately 100 human hearts.

The authors of the case report acknowledged they didn’t have a complete medical history for the man, but noted a potential link between the os cordis formation and his existing heart disease. Age and disease are known to influence the structure in other animals, too.

The discovery highlights the potential for anatomical variations that may go unnoticed in routine medical examinations. Further research is needed to understand the function, development, and prevalence of these cardiac structures in humans.