Dimples are genuine smiles are considered pretty attractive, but did you know that both these features are thanks to the actions of zygomaticus muscles?
These are actually two muscles: Major and Minor, present on both sides of your cheeks. They get their name for running over the surface of the zygomatic bone of the skull (yeah that bone that we like to call “cheekbone”). These muscles are part of a major group of muscles, facial muscles, which enable us to communicate with facial expressions, and in this case, smiling.
Cheek dimples are formed when the zygomaticus major has two strands and there’s a insertion of fibers into the skin, creating the appearance of what is known as dimples. Bilateral dimples are far more common than only on one cheek and while there’s a lot of debate whether it can be a trait inherited or not. The depth and shape is influenced by the shape of the skull and they can be present in young age and disappear later in life.
What does the Zygomaticus Muscles do?
Along with with Risorius, it pulls the corners of the Orbicularis oris, creating the effect of moving the mouth upwards when you smile. Without the action of zygomaticus, the smile looks insincere, because the skin around the eyes doesn’t get wrinkled.
Major: Pulls the angle of the mouth upwards. The overall effect of this muscle is pulling most of the lower face outwards and up. The lower eyelids is seen pushed onto the eyes and produces the wrinkles around the eye (often referred as crow’s feet at the outside corner of the eyes). There’s also a bit of action from the orbicularis oculi in this. The contraction of this muscle contributes to the expression of happiness, smiling, laughing and joy in general.
Minor: pulls the mid section of the upper lip on each corresponding side and the nasolabial furrow as well. This pull upwards and oblique, it’s rather more subtle than that of the levator labii superioris that pulls straight up. This muscle is also responsible for expressing sadness, as it draws the upper lip into a crying expression and even though it might seem similar to disgust, it’s not quite so.
As mentioned before, it’s also responsible for cheek dimples, either bilateral or unilateral, as the head of the zygomaticus major can be bifid and be inserted into the skin over the cheeks, leaving a small gap that forms the dimple.
Getting dimples for aesthetic reasons
Since dimples are considered an attractive trait to have, some women undergo surgery to get dimples. Sometimes on one side or both sides of the face. This procedure comes with minor complications such as swelling and hematomas in some cases.
Zygomaticus Muscle Fact sheet
Zygomatic and Buccal branches of the Facial nerve (VII)
Anterior surface of the Zygomatic bone.
Major: Modiolus of the mouth
Minor: Skin in the mid section of the nasolabial furrow and cheek’s subcutaneous fat. Other fibers can insert on the lips and on Orbicularis Oris.
Standring, Susan. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. , 2016. Print.