Cheek dimples are the result of a muscle in the cheek splitting in two.
Before birth, the zygomaticus major (a muscle that controls facial
expression, drawing the mouth's angle upward and outward) splits into a superior bundle positioned above
the corner of the mouth, and an inferior bundle below the corner of the mouth.
This creates a hammock effect where skin hangs in slightly between the two
bundles. When you smile, the muscles contract and the dimples are more
prominent due to increased skin tension.
