Week 3: Infratemporal fossa and TMJ

Question 1

What are the borders of the infratemporal fossa?

Answer 1

• medial: lateral pterygoid plate
• posterior: styloid process
• anterior: maxilla
• superior: greater wing of sphenoid+temporal+zygomatic arch

Question 2

What are the muscles of mastication?

Answer 2

• temporalis
• masseter
• buccinator muscle
• lateral pterygoid, medial pterygoid

Question 3

Describe the temporomandibular joint and how it functions in opening and closing the jaw.

Answer 3

• anatomy: mandibular head in mandibular fossa. Anterior is the articular eminence/tubercle.
• Synovial joint: with spaces above and below the articular disc between the mandibular fossa and head
  1. Disk and condyle (head) glides forward so articular tubercle is over head due to lateral pterygoid contraction
  2. condyle hinges open on tubercle in lower joint space

Question 4

What happens when the condyle moves anterior to the articular tubercle?

Answer 4

-jaw is dislocated

Question 5

Describe the actions of the muscles of mastication.

Answer 5

1. depression: lateral pterygoids, gravity
2. Elevation: masseter, temporalis, medial pterygoids
3. protrusion: mostly medial and lateral pterygoids and masseter
4. retrusion: temporalis, mostly its horizontal fibers
5. lateral motion: lateral and medial pterygoids

Question 6

What are the symptoms of TMJ disorder?

Answer 6

• pronounced joint noises associated with movement
• pain upon palpation of muscles of TMJ
• limited range of opening

Question 7

What are the branches of the mandibular nerve (V3) and its components?

Answer 7

A BLIMP
1. Buccal nerve- SS to mucosa inside of cheek and skin outside
2. Lingual nerve- SS to anterior 1/3 of tongue
3. inferior alveolar nerve- SS to all lower teeth, becomes cutaneous branch–>mental nerve
4. mylohyoid nerve- SS and SM to mylohyoid and anterior digastric muscles, cutaneous part only has SS. Comes off inferior alveolar
Also
6. Auriculotemporal-SS -circles middle meningeal artery and moves up vertically to skin on side of head and ear
7. Chorda tympani (branch of CN VII)- para/pre and taste-joins lingual nerve

Question 8

Describe the course of the chord tympani and lingual nerve. What are the components of the lingual nerve as it heads for the tongue.

Answer 8

The chord tympani hitchhikes onto the lingual nerve, synapses on submandibular ganglion, para goes to submandibular and sublingual gland. Taste goes to tongue

• Lingual before chorda tympani only has SS
• Lingual: SS, taste and para/pre after chorda tympani joins
• Lingual after ganglion: para/post and SS and taste

Question 9

What is trigeminal neuralgia (tic Douloureux)?

Answer 9

• severe pain, paroxysmal stabbing or burning, along the distribution of the trigeminal nerve
• can be in the distribution of one or more divisions of the trigeminal nerve, usually unilateral
• anatomic basis of neuralgia is abnormal activation of CN V
• treatment: neuroactive medications, injections, ablation, surgery