Depressor labii inferioris

The depressor labii inferioris (Latin: musculus depressor labii inferioris) is a facial muscle located below the lower lip in the chin area. It is classified as the buccolabial facial muscle. The depressor labii inferioris pulls the lower lip downward and forward.

Origin

The depressor labii inferioris originates from the oblique line located on the external surface of the mandibular base.

Insertion

The depressor labii inferioris inserts into the skin of the lower lip.

Action

Upon activation, the depressor labii inferioris muscle pulls the lower lip downward and forward. Contractions of the depressor labii inferioris participate in producing facial expressions of perseverance and diligence.

Innervation

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

Blood supply

The depressor labii inferioris receives arterial blood supply from the inferior labial branch of the facial artery and mental branch of the maxillary artery.