[1] It inserts on the skin of the lower lip, blending in with the orbicularis oris muscle around 2 cm wide.

The depressor labii inferioris muscle is supplied by the marginal mandibular branch of the facial nerve.

[1][2] The depressor labii inferioris muscle helps to depress and everts the lower lip.

[1] The depressor labii inferioris muscle may be resected (cut and removed) using surgery to correct an asymmetry of the lower lip when smiling.

This article incorporates text in the public domain from page 383 of the 20th edition of Gray's Anatomy (1918)