The mentalis is a somewhat conical-shaped, paired facial muscle that belongs to the oral group. It is positioned at the tip of the chin. The mentalis is also known as the pouting muscle, as it elevates the skin of the chin and raises and protrudes the lower lip, producing small dimples in the skin of the chin.

The upper aspect of this muscle is covered by the depressor labii inferioris muscle, while the lower portion lies within the subcutaneous tissue. All fibers of the mentalis radiate from their origin and insert into the skin of the chin, shaping its characteristic dome-like contour. In some cases, it also contributes to the formation of a mental crease - a depression in the midline beneath the lower lip.

Several studies have identified three anatomical variations of the mentalis muscles. In the first type, the muscle is merged at the middle with its counterpart, forming a continuous structure. The second type consists of two distinct, separate mentalis muscles without any fusion. The third type is characterized by a flat mentalis muscle composed of only a few muscle fibers.

Origin: alveolar process of the mandible near the root of the lateral incisor.

Insertion: fibers radiate and insert into the skin and soft tissue of the chin.

Action: raises the skin of the chin and the central part of the lower lip. Together with the orbicularis oris, it protrudes the lower lip. It also wrinkles the skin of the chin, producing small dimples. Contractions of this muscle contribute to facial expressions of doubt, contempt, and sadness.

Innervation: marginal mandibular branch of the facial nerve (CN VII).

Arterial blood supply: inferior labial and labiomental arteries of the facial artery and the mental branch of the inferior alveolar artery (a branch of the maxillary artery).

Venous drainage: inferior labial vein and submental vein, which drain into the facial vein.

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Mentalis