TCM (Traditional Chinese Medicine) tongue diagnosis is a crucial component of the TCM inspection method. It holds that the tongue is not only a part of the digestive system but also a direct reflection of the functional status of internal organs, qi, blood, and body fluids. Since the tongue’s shape is determined by muscle—an aspect governed by the spleen—observing its form can offer insights into the health of the spleen and, by extension, the entire body. This article, from the perspective of TCM tongue diagnosis, provides a detailed explanation of the various tongue shapes and the corresponding internal pathological changes,…