When a person smiles or makes other animated expressions, they may notice their chin skin appears bunched, dimpled, or protrudes. This aesthetic concern focuses on the soft tissue of the chin changing texture or projection during facial movement. Understanding the underlying anatomy and muscle dynamics is the first step toward finding solutions for this common phenomenon.
What is Mentalis Strain
The visual effect of a textured or uneven chin surface is commonly referred to as “mentalis strain.” Practitioners frequently use descriptive terms like “orange peel chin,” “pebbled chin,” or peau d’orange to describe this distinct appearance. This condition is characterized by small depressions, pitting, or a bumpy texture resembling the skin of an orange. This phenomenon occurs when the muscle beneath the chin is under tension, causing the overlying skin to wrinkle and gather. The severity of the dimpling can vary greatly, sometimes appearing only during intense facial animation.
The term “mentalis hypertonicity” is the medical description for this muscle overactivity, indicating the muscle has an excessive tone. This strain often results from a subconscious attempt to achieve “lip competence,” the ability to comfortably close the lips at rest. Individuals with a slightly recessed or underdeveloped lower jaw may habitually strain the chin muscle to help seal the lips, leading to this strained look over time.
How the Mentalis Muscle Causes Protrusion
The anatomical cause of chin dimpling and temporary protrusion lies with the mentalis muscle, a small but powerful paired muscle. Located centrally at the tip of the chin, it originates from the mandible and inserts directly into the soft tissue. Its primary function is the upward and inward movement of the chin soft tissue, which also helps to elevate and protrude the lower lip.
When a person smiles or speaks, the mentalis muscle contracts, pulling the soft tissue pad upward and creating a wrinkled or dimpled effect on the skin’s surface. This hyperactive contraction shortens the chin’s soft tissue envelope, causing the skin to bunch up and resulting in visible protrusion and dimpling. The degree of protrusion experienced is directly related to the strength and overactivity of this muscle. In some cases, the hyperactivity is an attempt to compensate for underlying structural issues, which forces the muscle to work harder to achieve a closed mouth posture.
Treating Muscle Overactivity with Injections
The most common non-surgical treatment for mentalis hypertonicity is the use of injectable neuromodulators, such as Botulinum Toxin Type A products (e.g., Botox, Dysport, or Xeomin). These purified proteins target the chemical signals that tell the mentalis muscle to contract. By blocking the release of the neurotransmitter acetylcholine at the nerve-muscle junction, the neuromodulator temporarily weakens or relaxes the overactive muscle.
This controlled relaxation of the mentalis muscle releases the upward and inward pull on the chin’s soft tissue pad. The result is a noticeable smoothing of the chin texture, reducing the appearance of dimpling and the dynamic protrusion that occurs during expression. The procedure is quick, taking less than fifteen minutes, and involves minimal downtime. Patients typically see effects within three to five days, with the full result appearing around two weeks. The smoothing effect lasts for approximately three to five months, requiring repeat treatments to maintain the desired appearance.
Addressing Underlying Volume and Structure
While muscle relaxation addresses surface texture and dynamic movement, chin protrusion can also relate to underlying bone structure or age-related changes. A naturally small or recessed chin, known as microgenia, can exacerbate mentalis strain because the muscle constantly compensates. In these instances, a structural approach is necessary to provide foundational support to the lower face.
Dermal fillers, typically composed of hyaluronic acid, are used to augment the chin non-surgically, improving its projection and overall shape. These viscous fillers are injected deep, often near the underlying bone, to add volume and enhance the chin’s horizontal dimension. By improving the structural foundation and balancing the chin with the rest of the facial features, the strain placed on the mentalis muscle may be reduced. This structural augmentation can be performed with neuromodulator injections, offering a comprehensive treatment that smooths skin texture while simultaneously improving the chin’s profile and projection.