de Ketham revisited: a modern-day urine wheel

During the Middle Ages, uroscopy was an important tool for evaluating health, and medical practitioners often carried Johannes de Ketham’s urine wheel as a diagnostic aid. In honour of de Ketham, a modern urine wheel is presented, which may be a useful diagnostic tool for present-day physicians.

Hippocrates, Aristotle and the ancient Egyptians inferred diagnoses from urine evaluation, but it was not until the Middle Ages that uroscopy reached diagnostic dominance. A major reason for its rise to prominence was the publication of Johannes de Ketham’s Fasciculus medicinae in 1491.1 This was the first illustrated medical book printed and is also among the most beautiful of such texts. The importance it places on urine evaluation is evident on page 1b, which depicts a urine wheel: a large circle surrounded by 21 thin-necked, urine-filled flasks (matulae) (Box 1). This wheel shows how the colour and consistency of urine could be matched to a diagnosis. Disease was thought to result from the imbalance of humours, reflected by urine colour. In the corners of the urine wheel, four small circles contain descriptions of the four temperaments: sanguineous, choleric, phlegmatic and melancholic.