Head & Neck Muscles

• List the muscles of mastication

  masseter, temporalis, lateral pterygoid, medial pterygoid
• List the muscles of facial expression

  occipitofrontalis, obicularis oculi, obicularis oris, zygomaticus major, zygomaticus minor, mentalis, buccinator, platysma
• What is the origin of the frontalis muscle?


  epicranial aponeurosis / galea aponeurotica
• What is the insertion of the frontalis muscle?


  skin superior to supraorbital margin and supraorbital muscles (procerus, corrugator supercilii, orbicularis oculi)
• What is the action of the frontalis muscle?

  moves scalp anteriorly, raise eyebrows, wrinkles skin of forehead horizontally. Expression = surprise
• What is the frontalis muscle an antagonist of?

  orbicularis oculi
• Compare the shapes/size of frontalis and occipitalis

  Frontalis is broader and longer than occipitalis and has no bony attachment. Occipitalis is shorter and narrower than frontalis and does have a bony attachment
• What is the origin of the occipitalis muscle?

  occipital bone and mastoid process of temporal bone. Lateral 2/3rds of superior nuchal line.
• What is the insertion of the occipitalis muscle?


  epicranial aponeurosis
• What is the action of the occipitalis muscle?

  draws scalp posteriorly
• What is the origin of the orbicularis oculi muscle?

  medial wall of orbit
• What is the insertion of the orbicularis oculi muscle?


  circular path around orbit
• What is the action of the orbicularis oculi muscle?


  closes eye
• What is the origin of the zygomaticus minor muscle?

  zygomatic bone
• What is the insertion of the zygomaticus minor muscle?


  upper lip
• What is the action of the zygomaticus minor muscle?

  raises (elevates) upper lip, exposing maxillary (upper) teeth
• What is the origin of the zygomaticus major muscle?

  zygomatic bone
• What is the insertion of the zygomaticus major muscle?


  skin at angle of mouth and blends with fibres of orbicularis oris
• What is the action of the zygomaticus major muscle?


  draws angle of mouth superiorly and laterally (smiling)
• What is the origin of the platysma muscle?

  fascia over deltoid and pectoralis major muscles
• What is the insertion of the platysma muscle?

  mandible, blends with muscles around angle of mouth, skin of lower face.
• What is the action of the platysma muscle?

  draws outer part of lower lip inferiorly and posteriorly = pouting. Depresses the mandible.
• What is the structure of the orbicularis oris muscle?

  not elliptical, has four quadrants: x2 pars peripheralis and 2x pars marginalis
• What is the origin of the orbicularis oris muscle?

  skin and muscle fibres surrounding lips
• what is the insertion of the orbicularis oris muscle?

  mucous membrane of lips at corner of mouth
• Orbicularis oris muscle action

  compresses and protrudes lips against teeth, shapes lips during speech. (kissing)
• What nerve innervates all muscles of facial expression?

  facial nerve CNVII (7th cranial nerve)
• mentalis muscle origin


  incisive fossa of mandible
• mentalis muscle insertion


  skin of chin
• mentalis muscle action


  wrinkles chin, protrudes and everts lower lip, raises lower lip and mentolabial sulcus. Expression = pout, disdain, doubt
• structure of mentalis muscle

  vertical orientation, cone shaped, lies lateral to frenulum of lower lip, courses inferiorly
• buccinator muscle origin


  pterygomandibular raphe and lateral surface of alveolar process of maxilla and mandible in region of molars.
• buccinator muscle insertion


  blend with orbicularis oris and submucosa
• buccinator muscle action


  compress cheeks against teeth and lips, whistling, blowing, sucking, draws corners of mouth laterally
• buccinator muscle structure


  transverse and anterior orientation, quadrilateral muscle, deepest extrinsic muscle of the lips, fibres course anteriorly and medial, central fibres of muscle decussate
• masseter muscle origin


  zygomatic arch and maxilla
• masseter muscle insertion


  lateral surface of mandibular ramus and angle
• masseter muscle action


  Elevation, protrusion, lateral deviation of mandible at temporomandibular joint.
• what innervates all muscles of mastication?

  trigeminal nerve (CNV)
• masseter internal muscle structure


  multipennate