1. Platysma
Origin: Fascia covering the deltoid and pectoralis major muscles
Insertion: Lower border of the mandible
Action: Depresses and retracts the lower lip, creating a pout, and lowers the jaw.
2. Depressor Labii Inferioris
Origin: Lower portion of the mandible
Insertion: Skin of the lower lip
Action: Lowers the lower lip.
3. Orbicularis Oris
Origin: Muscle fibers surrounding the oral cavity
Insertion: Skin at the corners of the mouth
Action: Closes and protrudes the lips, compresses them against the teeth, and shapes them for speech and kissing.
4. Corrugator Supercilii
Origin: Medial aspect of the brow ridge on the frontal bone
Insertion: Skin above the eyebrow
Action: Draws the eyebrows downward and creates vertical wrinkles in the forehead.
5. Orbicularis Oculi
Origin: Medial part of the orbital rim
Insertion: Circular path around the eye socket
Action: Closes the eyelids.
6. Occipitofrontalis
Origin: Epicranial aponeurosis
Insertion: Skin above the supraorbital ridge
Action: Moves the scalp forward, raises the eyebrows, and forms horizontal lines on the forehead.