1. Platysma
Origin: fascia of the pectoral and deltoid muscles
Insertion: medial fibers insert onto the lower border of the mandible or the skin of the lower lip
Action: releases pressure of skin on the subjacent veins, depresses mandible, pulls angle of mouth downwards
2. Mentalis
Origin: mental protuberance of the mandible near the midline
Insertion: angle of mouth, intermingle with other muscles, extends further into skin of lower lip up to midline
Action: elevates and portrudes the lower lip, accentuates the nasolabial furrow
3. Orbicular oris
Origin: from the modiolus on each side
Insertion: onto the skin and mucous membrane of lips
Action: closes the lips to narrow oral opening
4. Corrugator supercilii
Origin: superciliary arch
Insertion: onto the deep surface of the skin of the eyebrow
Action: draws eyebrows in an inferomedial direction, produces vertical wrinkles of the forehead in frowning
5. Orbicularis oculi
Origin: nasal part of the frontal bone
Insertion: lateral palpebral ligament
Action: closing eyelids both voluntarily and involuntary
6. Occipitofrontalis
Origin: lateral two-thirds of the superior nuchal line of the occipital bone
Insertion: nears into the epicranial aponeurosis
Action: moves the scalp forward, lifts eyebrows with the upper eyelid skin