9.2 The TMJ and Infratemporal Fossa

Question 1

What is the temporomandibular joint?

Answer 1

Articulation between the mandibular fossa, the articular tubercle and the head of the manbible allowing movements of the jaw

Question 2

What separates the two bones?

Answer 2

Fibrocartilage disk- creates two synovial cavities

Question 3

Why is the articular disk needed?

Answer 3

The bones are poorly aligned so the disk allows them to fit together.

Question 4

Describe the capsule surrounding the TMJ

Answer 4

Thin and loose- allows movement but sacrifices stability

Question 5

Name the 2 ligaments around the TMJ

Answer 5

Temporomandibular ligament x2

Medial ligament x2

Question 6

Name the 2 accessory ligaments surrounding the TMJ

Answer 6

Sphenomandibular

Stylomandibular

Question 7

What is the function of the sphenomandibular ligament?

Answer 7

Prevents inferior dislocation of the jaw

Question 8

Why is dental hygiene important for the stability of the TMJ?

Answer 8

The jaw becomes much more stable when the jaw is closed

Question 9

Which structure limits posterior dislocation?

Answer 9

The posterior glenoid tubercles

Question 10

Which structure limits anterior dislocation?

Answer 10

Articular tubercle

Question 11

What movement does the superior cavity produce?

Answer 11

Translation of the mandible

Question 12

What movement does the inferior cavity produce?

Answer 12

Rotation of the mandible

Question 13

Describe the process of closing the mouth

Answer 13

Posterior fibres of temporalis pull mandible backwards

Temporalis, masseter and medial pterygoid elevate the mandible

Question 14

Describe the process of opening the mouth

Answer 14

Condyles pulled forward by lateral pterygoids

Chin pulled down and back by digastric muscles in lower cavity

Question 15

What is bruxism?

Answer 15

Grinding of the teeth at night

Question 16

Where is the infratemporal fossa located?

Answer 16

Below middle cranial fossa
Deep to zygomatic arch
Behind maxilla

Question 17

Describe the borders of the infratemporal fossa

Answer 17

Anterior: Posterior surface of maxilla
Posterior: carotid sheath
Lateral: ramus of mandible
Medial: Lateral pterygoid plate of the sphenoid
Floor: Medial pterygoid muscle
Roof: Greater wing of sphenoid

Question 18

Name the 3 muscles which lie in the infratemporal fossa

Answer 18

Lower part of temporalis
Lower part of medial pterygoid
Lower part of lateral pterygoid

Question 19

Which nerves lie in the infratemporal fossa?

Answer 19

Mandibular nerve
Chorda tympani
Otic ganglion

Question 20

Which artery lies in the infratemporal fossa?

Answer 20

Maxillary artery which becomes the middle meningeal artery

Question 21

Which artery lies superficially to the infratemporal fossa?

Answer 21

Superficial temporal artery

Question 22

Which veins pass through the infratemporal fossa?

Answer 22

Pterygoid venous plexus
Maxillary vein
Middle meningeal vein

Question 23

Name the 5 openings of the infratemporal fossa

Answer 23

Foramen ovale
Foramen spinosum 
Alveloar canal 
Inferior orbital fissure
Pterygomaxillary fissure

Question 24

Why is the infratemporal fossa a potentially dangerous place to grow a tumour?

Answer 24

Tumour can grow relatively large without being detected as it fills the potential space.
Will present late with numbing of the teeth and lips