Myology 1 HS 113

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Myology 1 (HS 113)
Lecture 4 Muscles of the Face (Continued)
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Muscles of Facial ExpressionMouth Muscles

• Levator Labii Superioris
• Main elevators of upper lip are levator labii
  superioris zygomaticus minor.
• Contraction alone will elevate upper lip as in
  showing someone our upper teeth.
• Zygomaticus Minor
• Blends with levator labii superioris
• Zygomaticus Major
• Contributes to smiling and laughing
• 6 muscles attach into modiolus (fibro muscular
  condensation ¼ lateral to angle of mouth)
  zygomaticus major, levator anguli oris, risorius,
  depressor anguli oris, buccinator, orbicularis
  oris.

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Levator Labii Superioris

• O Inferior orbital margin of the maxilla
• I Upper Lip
• A Elevation of Upper Lip
• N CN VII (Facial nerve)

Palpation page 51
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Zygomaticus Minor

• O Zygomatic bone
• I Upper Lip
• A Elevation of Upper Lip
• N CN VII (Facial nerve)

Palpation page 54
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Zygomaticus Major

• O Zygomatic bone
• I Angle of Mouth
• A Elevation of Angle of Mouth as in smiling.
  Also draws laterally at the angle of the mouth
• N CN VII (Facial nerve)

Palpation page 57
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Muscles of Facial ExpressionMouth Muscles

• Levator Anguli Oris
• Also known as the caninus because contraction can
  result in teeth especially canine tooth becoming
  visible Dracula expression.
• Contraction alone can manifest a sneer.

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Levator Anguli Oris

• O Maxilla, just inferior to the infraorbital
  foramen
• I Angle of Mouth
• A Elevation of Angle of Mouth
• N CN VII (Facial nerve)

Palpation page 60
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Muscles of Facial ExpressionMouth Muscles

• Risorius
• Drawing angle of mouth laterally is involved with
  grinning, smiling, and laughing.
• Depressor Anguli Oris
• Blends into the platysma
• Contribute to facial expression of sadness or
  uncertainty.
• Depressor Labii Inferioris
• Contribute to facial expressions of sorrow,
  doubt, and irony.

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Risorius

• O Fascia Superficial to
• Masseter
• I Angle of Mouth
• Action Draws Laterally the Angle
• of Mouth
• N CN VII (Facial nerve)

Palpation page 63
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Depressor Anguli Oris

• O Mandible
• I Angle of Mouth
• A Depresses the Angle of Mouth. Also assists
  the risorius in drawing the angle of the mouth
  laterally
• N CN VII (Facial nerve)

Palpation page 66
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Depressor Labii Inferioris

• O Mandible
• I Lower Lip
• A Depression of Lower Lip. Also assists in
  drawing the lower lip laterally and everting it.
• N CN VII (Facial nerve)

Palpation page 69
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Muscles of Facial ExpressionMouth Muscles

• Mentalis
• Contributes to facial expressions of doubt,
  pouting, or disdain
• Buccinator
• Parotid duct pierces through buccinator to enter
  mouth
• Action of compressing the cheeks against the
  teeth by the 2 buccinators working bilaterally is
  important for forcefully expelling air from the
  mouth.
• Latin word for trumpeter is buccinator
• Important with whistling, blowing up a balloon
  and with helping keep food from lingering in
  vestibule of mouth.
• Contributes to expression (puckering the cheeks)
  made when person eats something sour.
• Orbicularis Oris
• Causes kips to close and protrude as in puckering
  lips or whistling.

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Mentalis

• O Mandible
• I Skin of the Chin
• A -Elevation of Lower Lip
• -Eversion and Protracts the
• Lower Lip
• - Wrinkles the skin of the chin
• N CN VII (Facial nerve)

Palpation page 72
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Buccinator

• O Maxilla and Mandible
• I Lips (buccinator muscle is located in the
  tissue of the cheek)
• A Compression of Cheeks (against teeth)
• N CN VII (Facial nerve)

Palpation page 75
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Orbicularis Oris

• O Surrounds the mouth
• Action Closes mouth and
• protracts the lips
• N CN VII (Facial nerve)

Palpation page 77
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Muscles of Mastication(All attach onto the
mandible)

• Temporalis
• Contributes to side-to-side grinding (lateral
  deviation) of mandible.
• Tight temporalis may be involved with tension
  headaches and TMJ dysfunction
• Masseter
• Square-shaped muscle, divided into superficial
  deep layers.
• Prime mover of mandibular elevation at TMJ.
• Large parotid glands are superficial to masseter.
• Proportional to its size, strongest muscle in
  body.
• Lateral Pterygoid
• Aka external pterygoid.
• Lateral deviation is important for grinding and
  chewing food.
• Hypertonicity could excessively pull on TMJ
  structures causing dysfunction.
• Medial Pterygoid
• Aka internal pterygoid
• Fairly thick, quadrilateral muscle
• Fiber directions are identical to masseter but
  medial pterygoid is internal to mandible and
  masseter is external.

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Temporalis

• O Temporal fossa
• I Coronoid process/Ramus of mandible
• A Elevation of Mandible
• N CN V (Trigeminal nerve)

Palpation page 83
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Masseter

• O Inferior margins of both zygomatic bone and
  zygomatic arch of temporal bone
• I Angle, ramus, coronoid of a mandible
• A Elevates, protracts and retracts the mandible
• N CN V (Trigeminal Nerve)

Palpation page 86
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Lateral Pterygoid

• O Sphenoid bone
• I Mandible TMJ
• A Protraction of Mandible
• N CN V (Trigeminal nerve)

Palpation page 89
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Medial Pterygoid

• O Sphenoid bone
• I Internal surface of Mandible
• A Elevates and protracts the mandible
• N CN V (Trigeminal nerve)

Palpation page 92