How cheek dimples form
"Dimples are sometimes caused by a change in a facial muscle called the zygomaticus major. This muscle is involved in facial expression. It’s the one that helps to raise the corners of your mouth when you smile."
"In people without dimples, the zygomaticus major muscle usually begins at a bone in your cheek called the zygomatic bone. It then runs downward, connecting to the corner of your mouth."
"In people with dimples, the zygomaticus major may divide into two separate bundles of muscle on its way down to the mouth. One bundle connects at the corner of the mouth. The other bundle connects below the corner of the mouth and is also tethered to the skin above it."
"This split in the muscle can be referred to as a double or bifid zygomaticus major muscle. Movement of the skin over the double zygomaticus major muscle when you smile causes the dimple to form."
"Because cheek dimples can result from a muscular variation that occurs during fetal development, they’re sometimes mistakenly referred to as a birth defect."
"It’s important to remember that not only are cheek dimples rather common, but they also don’t have any negative health effects."