3) The Temporal Region & TMJ

Question 1

What are contents of the Infratemporal Fossa?

Answer 1

Inferior part of Temporalis muscle

Inferior parts of Medial & Lateral Pterygoid muscles

Question 2

What is the arterial supply to the infratemporal fossa?

Answer 2

Maxillary artery (branch of ECA)
Middle Meningeal artery (branch of maxillary)
Superficial temporal artery (branch of ECA)

Question 3

What is the venous drainage of the infratemporal fossa?

Answer 3

Maxillary vein
Middle Meningeal vein(s)
Pterygoid venous plexus

Question 4

Which nerves pass through the infratemporal fossa?

Answer 4

Mandibular nerve (branch of Trigem. CN Viii)
Branches of mandibular nerve
 - Auriculotemporal N
 - Inferior alveolar N
 - Lingual N
 - Buccal N
 - Chorda Tympani (branch of Facial N)
Otic Ganglion

Question 5

What are the openings of the infratemporal fossa?

Answer 5

Foramen ovale
Foramen spinosum
Alveolar canal
Inferior orbital fissure
Pterygomaxillary fissure

Question 6

What is a mandibular nerve block?

Answer 6

Anaesthetic injected near mandibular nerve, where it enters infratemporal fossa (near to foramen ovale)
Nerves affected:
Inferior alveolar, Lingual, Buccal, Auriculotemporal

Question 7

What is the purpose of an Inferior Alveolar Nerve block?

Answer 7

Dental procedures
Anaesthetic injected around mandibular foramen (passage for inf. alveolar n. & vessels) medial side of mandible
All mandibular teeth anaesthetised on med. side
Skin & mucous membranes of lower lip, labial alveolar mucosa, gingivae & skin also anasethetised (mental branch of Inf. alv)

Question 8

What is the Temporomandibular joint (TMJ)?

Answer 8

Modified hinge type synovial joint

between Mandible & Cranium

Question 9

What are the articular surfaces of the TMJ?

Answer 9

Superiorly:
Mandibular Fossa (posterior & concave)
Articular Tubercle (anterior & convex)

Inferiorly:
Head of mandible

Question 10

What is the articular disc of the TMJ?

Answer 10

Articular disc (Meniscus)
Tough fibrocartilage that separates the Superior & Inferior Articular cavities (each lined by synovial membranes)

Question 11

What movements can the TMJ create?

Answer 11

Flexion (elevation) - Closing the mouth
Extension (depression) - Opening the mouth
Gliding (translation) - Protrusion & Retrusion of jaw
Rotation (pivoting)

Always the mandible that displaces

Question 12

Describe the opening movements of the TMJ

Answer 12

Condyles pulled forwards (protrusion/gliding, lateral pterygoid)
Chin moves down & back (Hinge, usually by gravity)

Question 13

Describe the closing movements of the TMJ

Answer 13

Retraction of mandible (retrusion/gliding, posterior fibres of temporalis)
Elevation of mandible (Hinge, remainder of temporalis, masseter, medial pterygoid)

Question 14

What are the attachments of the TMJ’s fibrous capsule?

Answer 14

Superiorly: circumference of mandibular fossa & articular tubercle
Inferiorly: neck of condyle of mandible

Question 15

Which extra-capsular ligaments strengthen the TMJ?

Answer 15

Lateral: Temporomandibular ligament (strong)
Medial: Sphenomandibular ligament, Stylomandibular ligament (accessory ligaments)

Question 16

When is the TMJ most stable?

Answer 16

Jaw CLOSED

• mandibular condyle in contact with mandibular fossa
• teeth in ‘perfect’ occlusion

TMJ least stable when jaw OPEN

Question 17

When can dislocation of the TMJ occur?

Answer 17

Sideways blow to chin when mouth open
Yawning
Taking a large bite
With fractures of mandible

Question 18

What happens during dislocation of the TMJ?

Answer 18

Excessive contraction of lateral pterygoids
Heads of mandible dislocate anteriorly
Mouth remains depressed, unable to close mouth

Question 19

What is bruxism?

Answer 19

Grinding teeth when asleep