Dimples are a generic name for indentations of the skin. Dimples are produced when muscle fibers are attached. To the deep surface of the skin, such as in the cheek or chin, or where the skin is attached to bones by fibrous bands, such as the elbow, shoulder, and back.
Dimples are most likely to appear where the skin is most tightly attached to the underlying bone. Anatomist Dr. William Jollie, of the Medical College of Virginia, indicates that “dimples probably are due to some developmental fault in the connective tissue that binds skin to bone.”
So all this time we’ve envied those dimples but didn’t realize that they are exhibiting an anatomical flaw! And the tendency toward dimples seems to be hereditary. You have your father to blame, Michael Douglas.
From: When do fish sleep? by: David Feldman