Week 6 - TMJ, Temporal & Infratemporal Region

Question 1

What forms the TMJ ?

Answer 1

Mandibular fossa of temporal bone and condylar process of mandible.

Question 2

What type of joint is the TMJ ?

Answer 2

Modified hinge (atypical) synovial joint.

Question 3

What makes the TMJ a synovial joint ?

Answer 3

Has a joint capsule.

Question 4

What makes the TMJ a modified hinge ?

Answer 4

Permits gliding motions and some degree of rotation as well as elevation and depression.

Question 5

What makes the TMJ an atypical joint ?

Answer 5

Surfaces of articulating surfaces are covered in fibrocartilage rather than hyaline cartilage - this is however more typical for synovial joint.

Question 6

What are the names of the ligaments associated with the TMJ ?

Answer 6

2 extrinsic - sphenomandibular and stylomandibular ligament.
1 intrinsic - lateral ligament.

Question 7

Where is the sphenomandibular ligament and what is its function ?

Answer 7

From spine of sphenoid bone to lingual of mandible.
Main passive support of mandible (with MOM).

Question 8

Where is the stylomandibular ligament ?

Answer 8

From styloid process to angle of mandible - thickening of fibrous capsule of parotid gland.

Question 9

What is the function of the lateral ligament ?

Answer 9

Strengthens the joint laterally and acts to prevent posterior dislocation.

Question 10

What are the 5 movements of the TMJ ?

Answer 10

Protrusion, retraction, elevation, depression, lateral.

Question 11

What muscles contribute to elevation of the mandible (closing of the mouth) ?

Answer 11

Temporalis.
Masseter.
Medial pterygoid.

Question 12

What muscles contribute to depression of the mandible (opening of the mouth) ?

Answer 12

Lateral pterygoid.
Supra and infrahyoid muscles.

Question 13

What muscles contribute to protrusion of the mandible (protrude chin) ?

Answer 13

Lateral pterygoid.
Masseter.
Medial pterygoid.

Question 14

What muscles contribute to retrusion of the mandible (retrude chin) ?

Answer 14

Temporalis - posterior oblique and near horizontal fibres.

Question 15

What muscles contribute to lateral movements of the mandible (grinding and chewing) ?

Answer 15

Temporalis of same side.
Pterygoids of opposite side.
Masseter.

Question 16

When is the TMJ most unstable and results in anterior dislocation into Infratemporal fossa ?

Answer 16

Depression - when condylar processes move anteriorly.

Question 17

What is the origin of the temporalis ?

Answer 17

Floor of temporal fossa and deep surface of temporal fascia.

Question 18

What is the insertion of the temporalis ?

Answer 18

Medial surface of coronoid process of mandible.
Anterior border of the ramus of mandible near the last molar.

Question 19

What area does the temporalis occupy ?

Answer 19

Temporal fossa.

Question 20

What is the action of the temporalis ?

Answer 20

Retract and elevate mandible.

Question 21

What is the innervation of temporalis ?

Answer 21

Deep temporal nerve from anterior trunk of CNV3.

Question 22

What is the origin of masseter ?

Answer 22

Maxillary process of zygomatic bone and anterior 2/3 of inferior border of zygomatic arch.

Question 23

What is the insertion of the masseter ?

Answer 23

Angle and lateral surface of ramus of mandible.

Question 24

What is the action of the masseter ?

Answer 24

Elevates the mandible.

Question 25

What is the innervation of masseter ?

Answer 25

Masseteric nerve from anterior trunk of CNV3.

Question 26

What is the origin of the medial pterygoid ?

Answer 26

Deep head - medial surface of lateral pterygoid plate. Superficial head - maxillary tuberosity and pyramidal process of palatine bone.

Question 27

What is the insertion of the medial pterygoid ?

Answer 27

Medial surface of the ramus and angle of the mandible.

Question 28

What is the innervation of the medial pterygoid ?

Answer 28

Nerve to medial pterygoid from main trunk of CNV3.

Question 29

What is the origin of the lateral pterygoid ?

Answer 29

Upper head - infratemporal surface of greater wing of sphenoid bone. Lower head - lateral surface of lateral pterygoid plate.

Question 30

What is the insertion of the lateral pterygoid ?

Answer 30

Front of neck of the mandible.

Question 31

What is the action of the lateral pterygoid ?

Answer 31

Protrude and depress mandible and assists medial pterygoid in lateral movement.

Question 32

What is the innervation of the lateral pterygoid ?

Answer 32

Nerve to lateral pterygoid and buccal nerve from anterior trunk of CNV3.

Question 33

What is the relevance to dentures of the mylohyoid line ?

Answer 33

Lower denture must stop short of mylohyoid otherwise contraction would lift it when speaking of chewing.

Question 34

What is the relevance to Ludwig's angina of the mylohyoid line ?

Answer 34

Infection spread from lower teeth below mylohyoid line into floor of submandibular region.

Question 35

What is the relevance to prosthodontics of the oblique line ?

Answer 35

Buccal edge of the mandible should stop short of oblique line or buccinator will interfere.

Question 36

What is the superior and posterior border of the temporal fossa ?

Answer 36

Superior and inferior temporal lines.

Question 37

What is the anterior border of the temporal fossa ?

Answer 37

Frontal process of zygomatic bone and zygomatic process of frontal bone.

Question 38

What is the inferior border of the temporal fossa ?

Answer 38

Infratemporal crest deep to zygomatic arch.

Question 39

What is the floor of the temporal fossa ?

Answer 39

Frontal, parietal, temporal and greater wing of the sphenoid bone (including pterion).

Question 40

What is the roof of the temporal fossa ?

Answer 40

Temporal fascia.

Question 41

What is the temporal fascia ?

Answer 41

Tough layer of fascia to superior temporal line and splits into two layers inferiorly to attach to zygomatic arch.

Question 42

What is the function of the temporal fascia ?

Answer 42

Provides the resistance to masseter.

Question 43

What is the lateral boundary of infratemporal fossa ?

Answer 43

Ramus of the mandible.

Question 44

What is the medial boundary of infratemporal fossa ?

Answer 44

Lateral pterygoid plate of sphenoid bone.

Question 45

What is anterior boundary of infratemporal fossa ?

Answer 45

Posterior aspect of maxilla.

Question 46

What is posterior boundary of infratemporal fossa ?

Answer 46

Tympanic plate, mastoid and styloid processes.

Question 47

What is superior boundary of infratemporal fossa ?

Answer 47

Infratemporal crest of sphenoid bone.

Question 48

What is inferior boundary of infratemporal fossa ?

Answer 48

Angle of mandible.

Question 49

What 3 muscles are found in infratemporal fossa ?

Answer 49

Medial, lateral pterygoid and inferior part of temporalis.

Question 50

What are the two terminal branches of external carotid artery ?

Answer 50

Superficial temporal and maxillary.

Question 51

What are the 6 most relevant branches of maxillary artery ?

Answer 51

Middle meningeal. Inferior alveolar. Anterior and posterior deep temporal. Masseteric. Buccal. Superior alveolar.

Question 52

What foramen does the middle meningeal artery pass through to enter middle cranial fossa ?

Answer 52

Foramen spinosum.

Question 53

What foramen does inferior alveolar artery pass through to enter mandible ?

Answer 53

Mandibular foramen.

Question 54

What branch of the maxillary artery passes through mandibular notch ?

Answer 54

Masseteric artery.

Question 55

What does the middle meningeal artery supply ?

Answer 55

Dura matter of the brain.

Question 56

What anatomical landmark can be seen from the inside of the skull relevant to the middle meningeal artery ?

Answer 56

Middle meningeal groove.

Question 57

The middle meningeal artery passes through a split in what nerve ?

Answer 57

Auriculotemporal nerve branch of CNV3.

Question 58

What route does the anterior and posterior deep temporal arteries take in the infratemporal fossa ?

Answer 58

Pass superiorly and laterally across roof of infratemporal fossa.

Question 59

The masseteric artery supplies the masseter via what surface ?

Answer 59

Deep surface.

Question 60

What does the buccal artery supply ?

Answer 60

Buccinator, cheek and buccal oral mucosa.

Question 61

What is the 1st part of the maxillary artery called ?

Answer 61

Mandibular part.

Question 62

What is the 2nd part of the maxillary artery called ?

Answer 62

Pterygoid part.

Question 63

What is the 3rd part of the maxillary artery called ?

Answer 63

Pterygopalatine part.

Question 64

What muscle is the maxillary artery divided into parts in relation to ?

Answer 64

Lateral pterygoid.

Question 65

What two main arterial branches are associated with the mandibular part of the maxillary artery ?

Answer 65

Middle meningeal and inferior alveolar arteries.

Question 66

What three main arterial branches are associated with the pterygoid part of the maxillary artery ?

Answer 66

Anterior and posterior deep temporal, masseteric and buccal arteries.

Question 67

What main arterial branch is associated with the pterygopalatine part of the maxillary artery ?

Answer 67

Superior alveolar artery.

Question 68

What fissure and then fossa does the third part of maxillary artery enter (pterygopalatine part) ?

Answer 68

Pterygomaxillary fissure and into pterygopalatine fossa.

Question 69

What artery runs deep between lateral and medial pterygoid muscles ?

Answer 69

Maxillary artery - first part i.e. mandibular part with branches - middle meningeal and inferior alveolar.

Question 70

What fossa does the trigeminal ganglion lie ?

Answer 70

Middle cranial fossa.

Question 71

What foramen does the mandibular nerve (CNV3) pass through ?

Answer 71

Foramen ovale.

Question 72

What is the corticobulbar tract responsible for ?

Answer 72

Voluntary motor control of head (skeletal muscle) - including muscles of facial expression, infra/suprahyoids, intrinsic and extrinsic muscles of the tongue and muscles of mastication.

Question 73

Where is the primary motor cortex located ?

Answer 73

Anterior to central sulcus.

Question 74

What fibres run from primary motor cortex to internal capsule ?

Answer 74

Corona radiata.

Question 75

What area of the internal capsule does the corticobulbar tract run through towards the brainstem ?

Answer 75

Genu (central point of the triangle made by the internal capsule).

Question 76

What is the genu ? And where is it located ?

Answer 76

Tunnel of white matter through middle of basal ganglia beneath corona radiata.

Question 77

What motor cranial nerves are associated with the midbrain ?

Answer 77

CNIII (oculomotor) and CNIV (trochlear).

Question 78

What motor cranial nerves are associated with pons ?

Answer 78

CNV (trigeminal), CNVI (abducens), CNVII (facial).

Question 79

What motor cranial nerves are associated with medulla ?

Answer 79

CNIX (glossopharyngeal), CNX (vagus), CNXI (accessory, CNXII (hypoglossal).

Question 80

The 'nucleus ambiguwus' is a shared nucleus in the corticobulbar tract by what 2 cranial nerves ?

Answer 80

CNX and CNIX.

Question 81

What is pseudobulbar palsy ?

Answer 81

Mild form of weakness in associated muscles.

Question 82

What two cranial nerves are an exception to "bilateral rule of innervation" in corticobulbar tract ?

Answer 82

CNVII and CNXII.

Question 83

Explain why facial nerve's motor innervation differs from the "bilateral rule of innervation" in corticobulbar tract.

Answer 83

- Facial nuclei split into upper and lower. - Upper nuclei UMN - innervated bilaterally for ipsilateral side. - Lower nuclei UMN - single contralateral innervation to nucleus.

Question 84

Explain why hypoglossal nerve's motor innervation differs from the "bilateral rule of innervation" in corticobulbar tract.

Answer 84

Single contralateral innervation to nucleus.

Question 85

What makes trochlear nerve unusual in the corticobulbar tract ?

Answer 85

UMN innervation - bilateral. LMN innervation - contralateral. LMN crosses to opposite sides.