The explanation for these indentations begins with a specific facial muscle: the zygomaticus major. Its usual function is to raise the corners of the lips when we smile, allowing that universal expression of joy. However, in some people, this muscle has a very particular structural variation: it divides into two independent fascicles or muscle bundles.
Anatomy
This bifurcation causes the skin to be pulled unevenly when it contracts during a smile. The result is that small, visible depression on the cheek that we call a dimple. It is, therefore, a congenital characteristic of the muscle tissue, not a defect or a medical condition.
The Role of Subcutaneous Tissue
Muscles are not the only determining factor. The thickness of the fat layer under the skin also decisively influences the visibility of the dimple. When the adipose tissue is thinner, the indentation is more pronounced. Conversely, in faces with fuller cheeks, the dimple may be less prominent or even disappear completely. This explains why some people notice their dimples becoming more or less evident depending on weight fluctuations throughout their lives.
