TMJ, Face, Skull

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TMJ, Face, Skull
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TMJ

• Mandibular fossa of temporal bone with condyle of
  mandible
• Incongruent surfaces
• Two joint cavities with articular disc interposed
• Lower cavity hinge joint
• Upper joint gliding

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TMJ
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TMJ
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Mandible
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Mandible
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TMJ

• Capsule
• Surrounds the joint
• Encloses the disc
• Attaches above the margins of the mandibular
  fossa
• To the neck of the mandible
• Inner aspect of capsule attaches to disc
• Above disc capsule loose
• Below disc - taut

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TMJ Capsule
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TMJ Capsule
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TMJ

• Ligaments
• Lateral ligament - AKA TMJ ligament
• From zygomatic bone to run inferiorly and
  posteriorly to blend with the joint capsule to
  attach to lateral and posterior parts of the neck
  of the mandible
• Sphenomandibular
• Strong thin flat band lying on medial aspect of
  the joint
• Passes inferiorly and forwards from the spine of
  the sphenoid to the lingula
• Stylomandibular
• Extends from the apex of the styloid process to
  the lower part of the posterior border of the
  ramus of the mandible, near the angle

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TMJ Capsule
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TMJ

• Innervated by CN V, Mandibular branch
• Movements
• Elevation, depression, retraction, protraction,
  side to side
• Elevation and depression involves the hinge like
  rotation of the condyle against the disc in the
  lower compartment
• Protraction and retraction actions whereby the
  condyle and disc move as one unit against the
  mandibular fossa. In protraction the condyle and
  disc glide forwards so that the condyle rides on
  the articular eminence retraction opposite

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CN V Trigeminal
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TMJ Motions
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TMJ Motions
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TMJ

• Side to side grinding movements
• Mandible is alternately protracted and retracted
  with the two sides moving in opposite directions
  so that one side is protracted while the other is
  retracted
• Actions combined with elevation and depression,
  rhythmically and alternately

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Muscles of Mastication

• Masseter
• Temporalis
• Lateral pterygoid
• Medial pterygoid
• All innervated by CNV
• Opening of jaw (depression) primarily passive or
  gravity assist

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Masseter
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Temporalis
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Pterygoids
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Pterygoids
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Pterygoids
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Nerve Supply to Face

• Sensory by three divisions of CN V opthalmic,
  maxillary, mandibular
• Innervation of muscles of facial carried out by
  CN VII the Facial Nerve
• Origin, branches, motor functions, sensory
  functions, parasympatheric functions

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CN V
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CN V
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Sensory to Face
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Sensory
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Scalp

• Three Layers
• Outer skin
• Beneath that subcutaneous layer with many
  nerves and vessels running through here, binds
  skin to inner layer
• Galea Aponeurotica AKA epicranial aponeurosis
• Galea attaches to pericranium via loose CT
• This allows scalp to move over the skull
• Most muscles of face attach to skin, this
  arrangement allows them to be more mobile.

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Scalp
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Scalp
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CN VII The Facial Nerve

• Motor nerve to muscles of facial expression with
  one notable exception
• Origin lower pons
• Branches common nerve enters face
• Temporal
• Zygomatic
• Buccal
• Mandibular
• Cervical

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Motor to Face CNVII
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CN VII

• Motor Functions
• Muscles of facial expression
• External ear
• Sensory functions
• Ant. 2/3 of tongue
• Soft palate
• Pharynx
• Parasympathetic
• Gland stimulation

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CN VII
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Muscles of Facial Expression

• Primary action is to act as either a sphincter or
  dilator of the orifices of the face
• Facial expression is a by-product
• Orifices
• Lips labia
• Nose nares Nostrils, Septum, Ala, Apex, Root
• Eyelids palpebrae
• External Ear auricle, lobule soft portion

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Selected Muscles of Facial Expression learn

• Orbicularis Oculi
• Levator Palpebrae Superioris
• O Root of Orbital Cavity
• I Skin of upper eyelid
• A Raises upper eyelid
• N Note Well, Nerve CN III
• Ptosis is a condition of denervation to this
  muscle causing drooping of the eyelid, a clinical
  symptom indicating more loss

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Facial MM
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Facial MM
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Facial MM
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Facial MM
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Muscles Continued

• Occipitofrontalis
• Corrugator
• Auricular muscles of the ear ant., post., sup.
• Nose
• Nasalis
• Procerus
• Depressor Septi

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Facial MM
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Facial MM
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Ear MM
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Nose MM
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Nose MM
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Muscles

• Mouth
• Depressor anguli oris
• Depressor labii inferior
• Mentalis
• Risorius
• Orbicularis oris
• Buccinator
• Zygomaticus major
• Zygomaticus minor
• Levator labii superioris
• Platysma

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Platysma
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Mouth
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Facial MM
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Extra Occular Muscles of the Eye

• Muscles that move the eyeball
• Innervated by CN III (most), CN IV (1),CN VI (1)
• Many have an origin from the annulus tendinous, a
  common tendon ring attached around the optic
  canal
• Most attach to the sclera of the eyeball

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Eye MM
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Muscles

• Superior Rectus rotates eyeball upward and
  medially CN III
• Medial Rectus rotates medially (ADD) CN III
• Lateral Rectus rotates eyeball laterally (ABD)
  CN VI
• Inferior Rectus rotates eyeball downward and
  medially CN III

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Eye MM
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Eye MM
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Eye MM
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Eye MM
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Muscles

• Superior Oblique rotates eyeball downward and
  lateral CN IV
• Inferior Oblique rotates eyeball upward and
  lateral CN III
• Combined motions
• Up and medial sup.rectus
• Up and lateral inferior oblique
• Straight up sup. rectus and inf. oblique
• Straight down inf. rectus and sup. oblique
• Down and medial inferior rectus
• Down and lateral superior oblique
• Lateral Gaze ABD of one eye with ADD of the
  other

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Eye Movements
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Eye Movments
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Eye Movements