depressor labii inferioris muscle


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de·pres·sor la·bi·i in·fe·ri·o·ris mus·cle

(dĕ-pres'ōr lā'bē-ī in-fēr'ē-ōr'is mŭs'ĕl)
Origin, anterior portion of lower border of mandible; insertion, orbicularis oris musculus and skin of lower lip; action, depresses lower lip; nerve supply, facial.
Synonym(s): musculus depressor labii inferioris [TA] .
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References in periodicals archive ?
It emerges to the subcutaneous layer of the face through the mental foramen which lies deep to the depressor labii inferioris muscle. The foramen lies 3 cm lateral to the midline and 1 cm above the lower border of the mandible between the first and second premolar teeth (Figure 1(a) and Table 1) [13].
Caption: Figure 1: Anatomy of the supraorbital notch, infraorbital foramen, and mental foramen with corresponding neurovascular structures and the course of the auriculotemporal nerve: (a) 1 = supraorbital notch containing the supraorbital nerve and vessels; 2 = infraorbital foramen containing the infraorbital nerve and vessels; 3 = mental foramen containing the mental nerve and vessels; 4 = corrugator supercilii muscle, which is superficial to the supraorbital notch; 5 = levator labii superioris muscle, which is superficial to the infraorbital foramen; 6 = depressor labii inferioris muscle, which is superficial to the mental foramen, and (b) 7 = auriculotemporal nerve; 8 = temporalis muscle; P = parotid gland.
Resection of the depressor labii inferioris muscle on the contralateral side can improve facial symmetry at rest and with smiling.
It interdigitates with the depressor anguli oris, with orbicularis oris, and depressor labii inferioris muscles, and it goes backwards into the masseter muscle."
Later, major rami of the marginal mandibular branches divide and pass directly to the surface of the mandible to travel beneath the depressor anguli oris and depressor labii inferioris muscles (Dingman & Grab).