Tennis Courts in the Human Body: A Review of the Misleading Metaphor in Medical Literature

Medical literature is home to fancy descriptions, poetic metaphors, and ingenious comparisons. However, some comparisons can disguise the knowledge gap. Large surfaces in the human body, like the alveolar surface for gas exchange, villi for food absorption, and the endothelial lining of blood vessels, are frequently compared to a “tennis court.” This narrative review explores this metaphor in detail, the discrepancies and factual inaccuracies across medical literature. It highlights the inappropriate use of Euclidean geometry and introduces fractal geometry, a language to define roughness.