ACTIVITY 1

ESCOSURA, Clinen L._ACTIVITY 1

ESCOSURA, Clinen L._ACTIVITY 1

by Clinen Escosura -
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ACTIVITY 1

For each activity, read the questions and post your answers in the forum provided for that activity.

 

Name the muscle that may cause the following facial expression and write down its origin, insertion and action.

 

1. Platysma

  • Origin: The platysma develops from the fascia that covers the clavicle, the acromial region, and the superior portions of the pectoralis major and deltoid muscles.

  • Insertion: Lower border of mandible, skin of buccal/cheek region, lower lip, modiolus, orbicularis  oris, and in some cases, orbicularis oculi 

  • Action: Depresses the mandible and the angle of the mouth, tenses the skin of the lower face, and causes anterior neck.

2. Mentalis

  • Origin: The mandible (lower jaw) gives rise to the mentalis, which runs vertically from below the lower lip to the lower part of the chin.

  • Insertion: Skin of chin/mentolabial sulcus

  • Action: Elevates, everts, and protrudes lower lip, wrinkles skin of chin 

 3. Orbicularis Oris

  • Origin: Nasal frontal bone, maxillary frontal process, medial palpebral ligament, and lacrimal bone

  • Insertion: Skin and mucous membrane of lips

  • Action: This muscle stabilizes the lower lip, allowing it to pout. It causes the lower lip to protrude and the chin skin to rise.

 

4. Corrugator Supercilii

  • Origin: Corrugator supercilii extends cranially from the medial end of the superciliary arch of the frontal bone to the root of the nose. Its fibers extend diagonally, laterally, and slightly superiorly into the brow skin above the middle of the supraorbital margin.

  • Insertion: Skin above middle of supraorbital margin

  • Action: These muscles draw the two brows together medially and inferiorly, causing vertical wrinkles over the glabella and a frowning expression.

5. Orbicularis Oculi

  • Origin: Nasal part of frontal bone, frontal process of maxilla, medial palpebral ligament, lacrimal bone 

  • Insertion: Skin of orbital region, lateral palpebral raphe, superior and inferior tarsal plates 

  • Action: The orbicularis oculi muscle helps to close the eyelids and pump tears from the eye into the nasolacrimal duct system.

  6. Occipitofrontalis

  • Origin: Frontal belly (frontalis), the skin of eyebrow, and muscles of the forehead

  • Insertion: Epicranial aponeurosis

Action: The occipitofrontalis muscle's frontal part elevates the brows and wrinkles the forehead skin, while the occipital part retracts the scalp.