Depressor anguli oris

The depressor anguli oris (Latin: musculus depressor anguli oris) is a facial muscle located in the mouth area. It is classified as the buccolabial facial muscle. The depressor anguli oris is responsible for pulling the angle of the mouth downward, thus enabling a facial expression associated with frowning.

Origin

The depressor anguli oris originates from the base of the mandible, specifically, from the oblique line that runs in the posterior direction and from the mental tubercle. Both structures are located on the outer surface of the mandible.

Insertion

The depressor anguli oris inserts into the skin at the angle of the mouth.

Action

The primary function of the depressor anguli oris is to pull the angle of the mouth downward. Contractions of the depressor anguli oris muscle participate in producing a facial expression of sadness.

Innervation

The depressor anguli oris is innervated by the marginal mandibular branch of the facial nerve (CN VII).

Blood supply

The depressor anguli oris receives arterial blood supply mainly from the inferior labial branch of the facial artery.