DMFE II LECTURE 3: TMJ & Muscles of Mastication

What bone is this?

temporal bone

What bone is this?

Sphenoid bone

What bone is this?

Zygomatic bone

What bone is this?

Maxilla

What bone is this?

mandible

How many superior processes does the mandible have? What are the names?

2; the condyloid process and coronoid process

what is between the condyloid and coronoid process?

mandibular notch

1

angle

2

ramus

3

neck

4

Condyloid process (head)

5

mandibular notch

6

coronoid process

where do the mental nerves exit and provide sensory innervations to the chin and the mandibular teeth?

mental foramen

1

Body

2

mental foramen

The mental nodes are branches of the () nerve and the mandibular division of the () nerve

inferior alveolar; trigeminal

1

Mandibular foramen

2

submandibular fossa

the submandibular gland is pushed up against the ()

fossa

the inferior alveolar nerve enters into the mandibular canal via ()

mandibular foramen

what is the point at which the condyloid process of the mandible articulates with the temporal bone?

mandibular fossa

when the jaw is lowered, it is limited anteriorly by the ()

articular tubercle/eminence

2

articular tubercle

3

mandibular fossa

4

styloid process

5

mastoid process

6

external auditory meatus

the TMJ is a () joint at the articulation btwn the condyloid process of the mandible and the mandibular fossa of the temporal bone

synovial

1

mandibular condyle

2

inferior joint cavity

3

superior joint cavity

4

Mandibular fossa

5

articular disc

6

articular tubercle

7

articular capsule

8

ramus of mandible

Gliding movements are permitted in the () compartment such as (), (), and () movements

upper; protrusion, retraction, and lateral

what type of movements are occur in the lower compartment?

rotational movements such as elevation and depression

When would the TMJ be discolated?

if the condyloid process moves beyond the articular tubercle

What ligament limits posterior movement of the mandible?

temporomandibular ligament

1

joint capsule

2

temporomandibular ligament

What are the medial ligaments?

sphenomandibular ligaments and stylomandibular ligaments- both limit lateral movement

1

stylomandibular ligament

2

sphenomandibular ligament

1

lateral pterygoid muscle

2

medial pterygoid muscle

how many heads does the medial pterygoid muscle have?

2: deep and superficial

what is the deep head of the medial pterygoid muscle attached to?

medial aspect of the lateral ptergoid plates

what does the superficial head of the medial pterygoid muscle attach to?

maxilla and palatine bones

1

lateral pterygoids

2

medial pterygoids

how many heads does the lateral pterygoid muscle have?

2; superior and inferior

bilateral action of the medial pterygoid muscles () the jaw and assist in ()

close; protrusion

how does the jaw open

laterla pterygoid muscles out bilaterally and protrude the jaw

what do the fibers of the temporalis muscle attached onto?

the coronoid process of the mandible

temporalis muscle

which fibers run vertically and assist in closing the jaw?

anterior fibers

the posterior horizontal fibers will () the mandible

retract

masster muscle

how many heads does the masster muscle have?

2; superficial and deep

what does the masster muscle attach to?

zygomatic bone and zygomatic arch , ramus and angle

what muscle elevated the mandible to close the mouth?

masseter muscle

when is the jaw most stable?

when its closed and the teeth are in occlusion

what is the most common form of displacement?

anterior dislocation

what is anterior dislocation opposed by?

articular tubercle, lateral ligament, and contraction of medial pterygoid, masseter, and temporalis

1

Temporalis muscle

2

temporal fascia

masseter muscle

4

deep masseter

5

superficial masseter

6

parotid duct

7

buccinator muscle (not muscle of mastication)

1

Articular disc of temporomandibular joint

2

articular tubercle

3

lateral pterygoid muscle

4

medial pterygoid muscle

5

parotid duct

6

buccinator muscle

8

sphenomandibular ligament

7

pterygomandibular raphe

what do the muscle of mastication do?

elevate the mandible, called “elevators”

what are the four muscles of mastication?

temporalis pterygoid, massester pterygoid, lateral pterygoid, medial pterygoid

What muscle originates from the floor of the temporal fossa and deep temporal fascia?

temporalis

what muscle inserts at the ramus of mandible and coronoid process?

temporalis

what muscle elevates the mandible using posterior fibers?

temporalis

what muscle originates at the zygomatic arch and inserts at the mandible and coronoid process?

masseter

What muscle elevates and protrudes the mandible using deep fibers?

masseter

What muscle protrudes the mandible when acting together and produces side to side movements when acting alone?

lateral pterygoid

What muscle elevates the mandible, protrudes the mandible when acting together, protrudes the side of jaw when acting alone, and produces the grinding motion when acting alternately?

medial pterygoid

1

joint capsule

2

lateral (temporomandibular) ligament

3

sphenomandibular ligament

4

sphenomandibular ligament phantom

5

styloid process

6

stylomandibular ligament

What ligament permits side to side motion, protrusion, and retraction?

capsule

what is the lateral (TMJ) ligament?

thickened fibrous band of capsule

what ligament divides the TMJ into synovial compartments

articular disc