Quick Facts
Origin: Oblique line of mandible.
Insertion: Middle portion of lower lip.
Action: Depresses lower lip.
Innervation: Marginal mandibular branch of facial nerve (CN VII).
Arterial Supply: Inferior labial artery and mental branch of inferior alveolar artery.
Origin
The depressor labii inferioris muscle originates from the oblique line of the mandible, which sits between the mental symphysis and the mental foramen of the mandible (Standring, 2016).
Insertion
The fibers of the depressor labii inferioris muscle blend with the orbicularis oris muscle. It also blends with the platysma muscle inferiorly.
Actions
The depressor labii inferioris muscle depresses the lower lip. This action is used during mastication and when expressing some facial expressions (Standring, 2016).
List of Clinical Correlates
- Bell’s palsy
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.
