3. The Temporal Region and Temporomandibular Joint

Question 1

What does the infratemporal fossa contain?

Answer 1

Inferior part of temporalis muscle, and inferior parts of medial and lateral pterygoid muscles.

Question 2

What is the maxillary artery a branch of?

Answer 2

External carotid artery, its larger terminal branch.

Question 3

What is the middle meningeal artery a branch of?

Answer 3

The maxillary artery, which in term is a branch of the external carotid artery.

Question 4

What is the superficial temporal artery a branch of?

Answer 4

The external carotid artery, its smaller terminal branch.

Question 5

What are the veins of the infratemporal fossa?

Answer 5

Maxillary vein, middle meningeal vein, pterygoid venous plexus.

Question 6

What is the mandibular nerve a branch of?

Answer 6

The trigeminal nerve, CN V3.

Question 7

What are the branches of the mandibular nerve?

Answer 7

Auricular nerve, inferior alveolar nerve, lingual nerve, buccal nerve, chorda tympani (branch of facial nerve).

Question 8

What are the openings of the infratemporal fossa?

Answer 8

Foramen ovale, foramen spinosum, alveolar canal, inferior orbital fissure, pterygomaxillar fissure.

Question 9

What runs through the foramen ovale?

Answer 9

Mandibular division of the trigeminal nerve CN V3.

Question 10

What runs through the foramen spinosum?

Answer 10

Middle meningeal artery.

Question 11

What is mandibular nerve block?

Answer 11

Injection of anaesthetics near the mandibular nerve where it enters the infratemporal fossa near the foramen ovale.

Question 12

Which nerve are affected in mandibular nerve block?

Answer 12

Inferior alveolar, lingual, buccal, auriculotemporal.

Question 13

When are inferior alveolar nerve blocks used?

Answer 13

In dental procedues.

Question 14

What happens in an inferior alveolar nerve block?

Answer 14

Anaesthetic is injected around the mandibular foramen on the medial side of the mandible, where inferior alveolar nerve and vessels travel.

Question 15

What is anaesthetised in inferior alveolar nerve block?

Answer 15

All mandibular teeth on medial side, skin and mucous membranes of lower lip, labial alveolar mucosa, gingivae, skin.

Question 16

What type of joint is the temporomandibular joint?

Answer 16

Modified hinge type synovial joint.

Question 17

What are the bones in the temporomandibular joint?

Answer 17

Mandible and cranium.

Question 18

What are the superior surfaces in the TMJ?

Answer 18

Mandibular fossa - posterior and concave, and articular tubercle - anterior and convex.

Question 19

What is the inferior surface in the TMJ?

Answer 19

Head of the mandible.

Question 20

What is the articular disc of the TMJ?

Answer 20

Aka meniscus. It is made of tough fibrocartilage and creates two compartments - superior and inferior articular cavities lined by separate synovial membranes.

Question 21

What are the movements of the TMJ?

Answer 21

Flexion (closing mouth), extension (opening mouth), gliding (protrusion/retrusion of mouth), rotation (pivoting).

Question 22

Which muscles are involved in flexion/elevation of the TMJ?

Answer 22

Temporalis, masseter, medial pterygoid.

Question 23

Which muscles are involved in extension/depression of the TMJ?

Answer 23

GRAVITY, lateraly pterygoid, suprahyoid, infrahyoid.

Question 24

Which muscles are involved in gliding/translation of the TMJ?

Answer 24

Protrusion - lateral pterygoid, medial pterygoid, masseter.

Retrusion - temporalis, masseter.

Question 25

Describe the movements in opening the TMJ.

Answer 25

Condyles are pulled forwards in protrusion. The chin moves down and back in hinge movement.

Question 26

Describe the movements in closing the TMJ.

Answer 26

Retraction of the mandible by retrusion. Elevation of the mandible by hinge movement.

Question 27

What is the joint capsule of the TMJ like?

Answer 27

Loos and thin to permit movements of the joint but strengthened by extra-capsular ligaments.

Question 28

What are the attachments of the TMJ capsule?

Answer 28

Superiorly - circumference of the mandibular fossa and articular tubercle. Inferiorly - neck of the condyle of the mandible.

Question 29

What are the extra-capsular ligaments of the TMJ?

Answer 29

Lateral - one ligament 'temporomandibular ligament' strong, deep fibres blend with capsule. Medial - two accessory ligaments 'sphenomandibular ligament' and 'stylomandibular' ligament.

Question 30

What is the TMJ most stable and why?

Answer 30

Why the jaw is closed as the mandibular condyle is in contact with the mandibular fossa. The teeth are in occlusal contact.

Question 31

When is the TMJ least stable?

Answer 31

When the jaw is open.

Question 32

How can anterior dislocation of the TMJ occur?

Answer 32

During yawning or a large bite, excessive contraction of the lateral pterygoids cause head of mandible to dislocate anteriorly.

Question 33

How does anterior dislocation of TMJ present?

Answer 33

Lock jaw, patient can't close their mouth.

Question 34

What is the most common cause of dislocation of the TMJ?

Answer 34

Side-ways blow to the chin with open mouth so TMJ dislocates on side that receives blow.

Question 35

What is bruxism?

Answer 35

Grinding teeth when asleep.

Question 36

What is temporomandibular pain dysfunction disorder?

Answer 36

Muscular pain.

Question 37

What is mal-occlusion syndrome?

Answer 37

Muscular pain.