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. 

Depressor labii inferioris muscle with other facial muscles
Depressor labii inferioris by Anatomy Next
Depressor labii inferioris
OriginBase of the mandible
InsertionSkin of the lower lip
ActionPulls the lower lip downward and forward
InnervationMarginal mandibular branch of the facial nerve (CN VII)
  Blood supply     Inferior labial artery of the facial artery, mental artery of the maxillary artery    

 

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.

Depressor labii inferioris muscle origin and insertion
Origin and insertion of depressor labii inferioris by Anatomy Next

 

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.

Action of depressor labii inferioris muscle with facial expression
Action of depressor labii inferioris by Anatomy Next

 

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.