Muscles of facial expression

  • Functions
    • regulators of 3 openings
      • eyes
      • mouth
      • nose
    • Sphincters (circular), dilators (radial)
    • Facial expressions: secondary effects of their contractions
  • Supplied by
    • 7th cranial nerve
  • Developed from
    • 2nd pharyngeal arch
  • Represent panniculus carnosus
  • Actions
    • Frontalis
      • look upwards without moving head
    • Corrugator supercilii
      • frowing
      • vertical wrinkling of forehead
    • Orbicularis oculi
      • tight closure of eyes
    • Dilators of mouth
      • smile widely
    • Buccinator
      • puffing mouth
      • blowing forcefully
  • Facial expressions
    • Smiling & laughing
      • zygomaticus major
    • Grinning
      • risorius
    • Sadness
      • levator labii superiori
      • levator anguli oris
    • Grief
      • depressor anguli oris
    • Anger
      • Dilator naris
      • depressor septi
    • Contempt
      • zygomaticus minor
    • Doubt
      • mentalis
    • Surprise
      • Frontalis
    • Horror & fright
      • platysma

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Applied anatomy

  • Bell’s palsy
    • facial nerve paralysis
  • Horner’s syndrome
  • Tetanus
    • Risus sardonicus

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Neck muscles

  • Sternocleidomastoid & trapezius
    • Nerve: Spinal accessory nerve
    • torticollis
      • wry neck
  • Anterior triangle
    • Suprahyoid muscles
      • Digastric
      • stylohyoid
      • mylohyoid
      • geniohyoid
    • Infrahyoid muscles
      • sternohyoid
      • sternothyroid
      • thyrohyoid
      • omohyoid
  • Posterior triangle
    • splenius copitis
    • scalenius anterior
    • scalenius posterior
    • scalenius medius
    • inferior omohyoid
    • levator scapulae

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Muscles of mastication

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  • Masseter
  • Temporalis
  • Medial pterygoid
  • Lateral pterygoid

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Temporomandibular joint

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  • Synovial joint
    • bicondylar variety
  • Articular surfaces
    • Articular eminence
    • Mandibular fossa
      • anterior part
    • Head of mandible
      • condyloid process

Movements

  • Side-to-side
    • chewing
    • alternate contractions of medial & lateral pterygoids of opposite sides
  • Protrusion/protraction
    • simultaneous contraction of medial & lateral pterygoids of both sides
  • Retrusion/retraction
    • temporalis
  • Elevation
    • Masseter
    • temporalis
    • medial pterygoid
  • Depression
    • lateral pterygoid
    • infrahyoid muscles
    • gravity

Blood & nerve supply

  • Blood supply
    • Superficial temporal artery
    • maxillary artery
  • Nerve supply
    • Mandibular nerve
    • Auricotemporal nerve
    • Masseteric nerve

Applied anatomy

  • Jaw closed
    • occlusal position
    • stable position of joint
  • Injury impact forces
    • absorbed by teeth
  • Dislocation of the head anteriorly into the infratemporal fossa
  • Articular disc displacement

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