Face muscles

Adduction Overview

• Definition of Adduction: The process of bringing a limb or structure closer to the midline of the body.

Facial Muscles

• Importance of Facial Muscles:

  • Clinical relevance in cranial nerve testing.

  • Relevant to muscles of mastication and understanding brain stem function.

Buccinator Muscle

• Location:

  • Found in the cheek area.

• Function:

  • Holds food in place during mastication (chewing).

• Origin:

  • Posterior maxillary bone and mandible.

  • Positioned underneath the masseter muscle.

• Insertion:

  • Orbicularis oris (muscle around the mouth).

• Action:

  • Compresses the cheek to keep food inside the oral cavity.

Depressor Labii Inferioris

• Location:

  • Just lateral to the mentalis muscle.

• Function:

  • Lowers the lower lip, facilitating mouth opening for eating.

• Origin:

  • Mandible.

• Insertion:

  • Orbicularis oris and skin of the lower lip.

Levator Labii Superioris

• Location:

  • Above the lips.

• Function:

  • Elevates the upper lip.

• Origin:

  • Zygomatic bone and maxilla.

• Insertion:

  • Skin and muscle of the upper lip or orbicularis oris.

• Action:

  • Opens the mouth.

Mentalis Muscle

• Location:

  • Situated on the chin.

• Function:

  • Wrinkles the chin and protrudes the lower lip.

• Origin:

  • Mandible.

• Insertion:

  • Skin of the chin.

• Significance:

  • Works in conjunction with depressor labii inferioris for controlled lip movement.

Orbicularis Oris

• Type:

  • Sphincter muscle; encircles the lips.

• Function:

  • Closes the mouth and protrudes the lips.

• Origin:

  • Maxilla and mandible.

• Insertion:

  • Skin of the lips and around the mouth.

• Significance:

  • Works alongside the buccinator to keep food in the mouth during chewing.

Risorius Muscle

• Location:

  • Beneath the buccinator.

• Function:

  • Draws the corners of the mouth laterally.

• Origin:

  • Zygomatic bone and maxilla.

• Insertion:

  • Skin of the mouth at the angle.

Depressor Anguli Oris

• Function:

  • Draws the corner of the mouth laterally and inferiorly.

• Origin:

  • Mandible.

• Insertion:

  • Corner of the mouth.

Zygomaticus Major and Minor

• Definitions of Major and Minor:

  • Major: the larger muscle; Minor: the smaller muscle.

• Origin:

  • Both originate from the zygomatic arch (zygomatic bone).

• Insertion:

  • Both muscles insert into the corner of the mouth.

• Function:

  • Responsible for smiling; the muscle fibers pull upward towards the zygomatic arch during this expression.

Corrugator Supercilii

• Location:

  • Originates from the medial edge of the orbit on the frontal bone.

• Function:

  • Draws eyebrows together and wrinkles skin above the nose.

• Insertion:

  • Skin of the medial part of the eyebrows.

Orbicularis Oculi

• Type:

  • Another sphincter muscle located in the orbit.

• Function:

  • Closes the eye.

• Origin:

  • Frontal and maxillary bones.

• Insertion:

  • Skin around the eyelids.