What anatomical feature was observed by the Hippocratic schools for prognosis of serious illnesses?

The Hippocratic schools recognized the face as a significant anatomical feature for assessing the prognosis of serious illnesses. They believed that various facial characteristics, including coloration, expression, and the presence of specific facial features, could provide insights into a person's health status. For instance, changes in skin tone or the appearance of the face could indicate different health conditions, ranging from feverish states to more chronic illnesses. This practice laid the groundwork for observing physical signs as indicators of internal health, which remains a cornerstone in medical diagnostics even today. The emphasis on the face in ancient medical writings illustrates the importance of visual cues in understanding a patient's condition.