The Secret Dimple: 5 Fascinating Facts About The Fovea Inferior Anguli Oris

Imagine a facial feature so rare that most people—even doctors—have never heard its name. As of today, December 17, 2025, the *fovea inferior anguli oris* remains one of the most obscure and fascinating anatomical variations of the human face. This tiny, often bilateral depression, located just below the corner of the mouth, is far less common than the beloved cheek dimple (*fovea buccalis*) and holds a unique place in the world of facial aesthetics and congenital anatomy. This article will delve into the precise anatomical makeup of this rare feature, explore its genetic origins, and detail the modern cosmetic procedures available for those who wish to either enhance or eliminate this subtle but distinct facial trait. Understanding this specific *fovea* requires a deep dive into the complex network of muscles that control your smile and frown, making it a crucial topic for anyone interested in high-level *perioral* aesthetics.

The Anatomy of Rarity: What Exactly is the Fovea Inferior Anguli Oris?

The term *fovea inferior anguli oris* (FIAO) translates directly from Latin to mean "pit below the angle of the mouth." This anatomical feature was formally named and documented in a 2017 study, highlighting its status as a recently recognized entity in medical literature. It is not a standard part of human anatomy but rather a congenital variation—a type of skin dimple. Unlike the common cheek dimple, which is typically found in the *buccal* area, the FIAO is situated specifically:

• Inferiorly: Below the horizontal line of the mouth corner.
• At the *Anguli Oris*: Very close to the *modiolus*, a dense, mobile knot of facial muscles where the lips meet.

The Muscular Mechanism Behind the Dimple

All facial dimples, including the rare FIAO, are generally caused by a minor, congenital variation in the attachment of underlying facial muscles to the overlying *dermis* (skin). When the muscle contracts, the short, fibrous attachment pulls the skin inward, creating the characteristic depression. In the case of the *fovea inferior anguli oris*, the dimple is intimately related to two key muscles responsible for depressing the lower lip and mouth corner:

1. The *Depressor Anguli Oris* (DAO) Muscle: This muscle pulls the corners of the mouth downward, contributing to expressions of sadness or frowning. The FIAO is located in the region of the DAO.
2. The *Depressor Labii Inferioris* Muscle: This muscle pulls the lower lip down.

It is hypothesized that a short, fibrous band of connective tissue connects the skin directly to the fascia or muscle fibers of the *Depressor Anguli Oris* or the *Orbicularis Oris* muscle complex in this specific location, causing the dimpling effect upon contraction.

Genetic Footprint: The Hereditary Nature of Lower Mouth Dimples

The occurrence of the *fovea inferior anguli oris* is not random; it is strongly linked to genetics. Dimples, in general, are considered an inherited trait, often passed down through families as a dominant characteristic. The 2017 case study that formally named the FIAO noted that the patient's grandmother also had the same bilateral dimples, while the mother had the more common *fovea buccalis* (cheek dimples). This observation reinforces the understanding that:

• It is Congenital: The feature is present from birth, not acquired later in life.
• It is Familial: A genetic predisposition is a primary factor in its existence.
• It is a Variant of Dimpling: The genes responsible for dimpling can manifest in different locations on the face, from the cheeks to the chin (*fovea mentalis*) and the lower mouth corner.

Aesthetic Significance and Modern Treatment Options

The presence of the *fovea inferior anguli oris* can be a source of curiosity, charm, or, for some, cosmetic concern. In the field of *perioral rejuvenation*, the area around the mouth is a major focus for restoring a youthful and harmonious appearance. The FIAO can be a unique, endearing feature, but it can also be perceived as an unwanted indentation that disrupts the smooth contour of the lower face, especially as the skin loses *collagen* and *elastin* with age. Modern aesthetic medicine offers several options for addressing the FIAO, depending on the patient's goal: enhancement or elimination.

Option 1: Elimination or Softening with Dermal Fillers

For individuals who perceive the lower mouth dimples as an unwanted indentation, especially when they are deep or appear to drag the mouth corner down, *dermal fillers* are the primary non-surgical solution. * Hyaluronic Acid (HA) Fillers: Soft, flexible HA fillers (such as Restylane or Juvederm products) can be precisely injected directly into the dimple's depression. * Mechanism: The filler adds *volume* beneath the skin, effectively lifting the indentation and smoothing out the contour of the *mandibular* border and lower lip area. This treatment is often part of a broader *perioral* treatment plan that may include addressing *marionette lines* and *oral commissures*. * Latest Techniques: Aesthetic practitioners use techniques like *micro-droplet injections* to carefully deposit the product only in the fovea, ensuring a natural result that doesn't overfill the surrounding tissues.

Option 2: Enhancement (Dimpleplasty)

While most *dimpleplasty* procedures focus on creating the more common *fovea buccalis* in the cheek, the same surgical principles can theoretically be adapted to create or deepen a dimple in the *anguli oris* region for patients who desire this specific look. * Procedure: The surgeon makes a small incision inside the mouth to access the underlying muscle tissue. A suture is then passed through the inside of the cheek and caught on the internal surface of the desired muscle (likely the *Depressor Anguli Oris* or surrounding fibers) and then secured to the undersurface of the *dermis*. * Outcome: This creates a permanent tether between the skin and the muscle, mimicking the natural anatomical variation of the *fovea inferior anguli oris*.

Option 3: Interaction with Botox/Toxin Injections

The *Depressor Anguli Oris* (DAO) muscle is a common target for *Botox* or other *neuromodulators*. Injecting the DAO can relax the muscle, preventing it from pulling the mouth corners down, thus creating a subtle *lip lift* or softening a downturned smile. * Clinical Consideration: A practitioner treating the DAO with *Botox* must be aware of the presence of an FIAO. Relaxing the DAO could potentially soften the appearance of the dimple, as the muscle that creates the pull is less active. Conversely, a patient seeking to eliminate the dimple might find a small dose of *neuromodulator* a less invasive alternative to fillers or surgery. This highlights the need for a detailed *facial assessment* before any *perioral* procedure.

5 Key Takeaways on the Fovea Inferior Anguli Oris

The *fovea inferior anguli oris* is more than just a rare dimple; it is a fascinating intersection of genetics, anatomy, and modern cosmetic desire.

1. Rarity Factor: It is significantly less common than the cheek dimple (*fovea buccalis*), making it a truly unique facial feature.
2. Anatomical Neighbors: Its location is critical, sitting near the *modiolus* and the *Depressor Anguli Oris* (DAO) muscle, which are key structures in facial expression and *perioral* aesthetics.
3. Congenital Cause: Like all dimples, its presence is a genetic and congenital variation, likely caused by a short fibrous connection between the skin and the underlying facial musculature.
4. Aesthetic Dualism: It is equally desired by some (leading to *dimpleplasty* requests) and disliked by others (leading to requests for *dermal filler* correction).
5. Clinical Relevance: Its presence is a crucial point of consideration for cosmetic injectors and plastic surgeons performing *perioral rejuvenation* procedures, especially when targeting the DAO muscle or using *hyaluronic acid* to smooth the lower face contour.