9.2

Question 1

What bony surfaces articulate in the TMJ?

Answer 1

Mandibular fossa
Articular tubercle (from squamous part of temporal bone)
Head/condyle of mandible

Question 2

What is found between the bony surfaces?

Answer 2

Articular fibrocartilage disc

Question 3

What covers the articulating surfaces?

Answer 3

Fibrocartilage

Question 4

What is the significance of the presence of the articular disc?

Answer 4

Makes articulating surfaces congruent.
Forms superior cavity between temporal bone and upper surface of disc.
Forms inferior cavity between mandibular condyle and inferior surface of disc.

Question 5

What is the shape of the articular disc?

Answer 5

Upper = concavo-convex to allow for the mandibular fossa and the articular tubercle.
Lower surface is concave to receive the mandibular condyle

Question 6

Describe the fibrous capsule of the TMJ and its attachments.

Answer 6

Thin and loose to permit movement.
Looseness makes it prone to sub laxation and dislocation.
Superiorly attaches to circumference of mandibular fossa
Inferiorly attaches to neck of mandibular condyle

Question 7

What are the 5 extra capsular ligaments that stabilise the TMJ?

Answer 7

Lateral temporomandibular ligament
2 Medial ligaments
Sphenomandibular ligament
Stylomandibular ligament

Question 8

Describe the temporomandibular ligament. What does it prevent?

Answer 8

Strongest
Lower border of zygoma to the neck and rams of mandible.
Thickening of joint capsule that acts to prevent posterior dislocation.

Question 9

Describe the sphenomandibular ligament.

Function?

Answer 9

Orginates orom the sphenoid spine and attaches to mandible
Remains constant length/tension in all movement.
Prevents inferior dislocation.

Question 10

Describe the stylomandibular ligament. Function?

Answer 10

Thickening of deep parotid fascia separating the parotid gland from the submandibular gland.
Extends from the apex of the styloid process to the posterior rams of the mandible.
Supports weight of the jaw.

Question 11

When is the TMJ most stable?

Answer 11

When closed
Mandibular condyle is in contact with mandibular fossa
Teeth are in occlusal contact.

Question 12

What limits posterior displacement?

Answer 12

Posterior glenoid tubercle and temporomandibular ligament

Question 13

What limits anterior displacement?

Answer 13

Articular tubercle

Question 14

What limits inferior dislocation

Answer 14

Sphenomandibular and stylomandibular ligaments

Question 15

What movements can occur at the TMJ and where do they occur?

Answer 15

Tranlastion at superior joint cavity
Protrusion and retraction

Rotation at inferior joint cavity
Depression and elevation

Question 16

What muscles are responsible for protrusion and retraction?

Answer 16

Protrusion - lateraal pterygoids

Retraction - geniohyoid and digastric, posteiror fibres of temporalis

Question 17

What muscles are responsible for depression?

Answer 17

Gravity

If resistance, digastric, geniohyoid, mylohyoid

Question 18

What muscles are responsible for election?

Answer 18

Temporalis, masseter and medial pterygoid.

Question 19

What causes the mouth to open?

Answer 19

Protrusion and depression

Question 20

What causes the mouth to close?

Answer 20

Retraction and elevation

Question 21

What happens if the TMJ is dislocated? What can be damaged? How can it happen

Answer 21

Patient is unable to close mouth s head of mandible slips out of mandibular fossa.
Facial nerve and auriculotemporal CNV3 can be damaged.
Yawning, trauma

Question 22

Where is the infra temporal ross located in terms of anatomic relation?

Answer 22

Deep to masseter
Below middle cranial fossa
Medial and deep to zygomatic arch
Behind the maxilla

Communicates with temporal fossa through the interval between zygomatic arch and cranial bones.

Question 23

What are the borders of the infra temporal fossa?

Answer 23

Lateral - rams of mandible
Medial - lateral pterygoid plate of sphenoid
Anterior - Posterior surface of the maxilla
Posterior - Carotid sheath
Superior - Greater wing of sphenoid
Inferior - Medial pterygoid muscle

Question 24

What muscles are found in the ITF

Answer 24

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

Question 25

What nerves run through the ITF?

Answer 25

Madibular nerve CNV3 (Branches - AUT, B, L ,IA) Chorda tympani of CNVII Otic ganglion

Question 26

What arteries are found in the ITF?

Answer 26

``` MAxillar A (from ECA) Maxillary A gives rise to MMA in fossa --> cranial cavity via foramen spinosum. ```

Question 27

What veins are located in the ITF?

Answer 27

``` Pterygoid venous plexus Connects ot cavernous sinus Drains eye and locality Infections of skin and eye socket can track back and cause meningitis. Maxillary vein MMV ```

Question 28

Describe fracture of the pterion and its significance. Symptoms? Treatment?

Answer 28

Pterion is where the temporal, frontal, parietal and sphenoid bone meet MMA supplies the skull and dura mater and travels beneath the pterion. If ruptures, blood collects between dura and skull causing increase in intracranial pressure (Extradural haematoma) Causes: nausea, vomiting, seizures, bradycardia, limb weakness Treated by diuretics or drilling burr holes for drainage.

Question 29

What openings re in the ITF?

Answer 29

``` Froament ovale (transmits CNV3) Foramen spinosum (MMA) Alveolar canal Infeiror orbital fissure Pterygomaxilary fissure ```