Anatomy

Question 1

How would you anatomically classify the TMJ?

Answer 1

Bilateral synovial diarthodial ginglymoid joint.

Question 2

Describe the three zones of articular surface of the condyle head

Is it comprised of vascular/avascular, innervated/non-innervated, lymphatic/alymphatic connective tissue?

Answer 2

Divided into three zones:

1. Fibrous connective tissue (durable, absorbs forces)
2. Zone of chrondogenesis (mesenchymal cells to repair)
3. Zone of secondary cartilage (converts cartilage to bone during growth)

Compromised of avascular, non-innervated, and lymphatic connective tissue

Question 3

Articular disk composed of?

Answer 3

1. Fibrocartilage? Some say it’s dense fibrous connective tissue. Seems like a debate on terminology

Question 4

How is the articular disk attached to the condyle head?

What effect do these attachments have on condylar movements?

Answer 4

Attached via medial and lateral poles

2. They prevent excess mediolateral mobility of the disk

Question 5

In sagittal view, how is the articular disk divided? (3)

Which is thinnest?

How are the fibrous connective tissue fibrils oriented?

Answer 5

1. Posterior band
2. Intermediate zone
3. Anterior band

Intermediate zone is thinnest

Intermediate zone: Oriented A-P.
Anterior and posterior band: Lateromedial direction

Question 6

Posterior band of articular disk continues with retrodiscal tissue composed of what kind of loose tissue that attaches inferiorly to what and superiorly to what?

Answer 6

1. Loose connective tissue
2. Posterior aspect of condylar head
3. Superiorly to glenoid fossa

Question 7

Retrodiscal tissue contains what? (5)

What three parts is it divided into?

Answer 7

1. Collagen fibers
2. Elastic fibers
3. Blood vessels
4. Lymphatics
5. Nerve endings

A. Temporal (attaches to temporal bone, elastic)
B. Intermediate (loose CT/elastic fibers, contains venous plexus)
C. Condylar (attaches to condyle, dense fibrous CT, helps stabilize)

Question 8

Histologically, the posterior band of the articular disk is identified as ___

Histologically, the retrodiscal tissue is identified as ___

Are either vascular?

Answer 8

1. Dense fibrous connective tissue with limited elasticity
2. Fibroelastic (due to its elastic tissues, loose connective tissues)

Retrodiscal tissue is vascular

Question 9

The anterior band of the articular disk’s dense fibrous connective tissue fibers blend with the fibers of which muscles anteromedially (1) and laterally (2)?

Answer 9

1. Anteromedially: Lateral pterygoid muscle (superior head)
2. Laterally: Masseter and temporalis muscles

Question 10

___ is a fibrous sheet that surrounds and limits the temporomandibular joint space.

___ ligament superficially reinforces the articular capsule with two layers. The deeper horizontal layer of the ligament layer does what, and the superficial oblique layer does what?

Answer 10

1. Articular capsule
2. Temporomandibular ligament
   2a. Horizontal - restrict posterior displacement and protects retrodiscal tissues
   2b. Limits transition of mandibular rotation resulting in translation of the condyle

Question 11

Articular capsule
- Innervation?
- Vasculation for posterior and anterior?

Answer 11

1. Branches of trigeminal nerve
   - Auriculotemporal nerve
2. Posteriorly: Superficial temporal and maxillary arteries Anteriorly: Masseteric and deep temporal

Question 12

Stylomandibular ligament

Origin
Insertion
Function?

Answer 12

Styloid process
Mandibular angle
Limits protrusion

Question 13

Sphenomandibular ligament

Origin
Insertion
Function

Answer 13

Sphenoid spine
Mandibular lingula
Suspends the mandible

Question 14

Temporomandibular ligament

Outer oblique portion’s
- Origin and Insertion
- Function?

Inner horizontal portion’s
- Origin and Insertion
- Function?

Answer 14

Zygomatic process and posterior condylar neck
F: Restricts condyle rotation movement resulting in translation

Articular tubercle and condylar lateral pole
F: Restricts posterior displacement protecting retrodiscal tissues

Question 15

Which muscles open the mandible? (4)

Answer 15

Lateral pterygoid
Suprahyoid group (digastric, geniohyoid, mylohyoid)

Question 16

Temporalis muscle

O
I
Action of vertical fibers and of posterior fibers?

Answer 16

Temporal fossa/side of skull
Coronoid process
Vertical fibers elevate and posterior fibers retried mandible

Question 17

Which muscles form the mandibular sling?

O’s? I’s?

Answer 17

Masseter
Zygomatic process to mandible angle

Medial pterygoid
Deep head: lateral Pterygoid plate
Superficial head: pyramidal process
Inserts to mandible angle

Question 18

Lateral pterygoid muscles (superior “upper” and inferior “lower”)

O’s, I’s, A’s?

Answer 18

Superior (“upper”) head of lateral pterygoid
O/I: Sphenoid wing into articular capsule, disc, and neck of condyle
A: Active during power stroke of mandible closure; stabilize disc/condyle

Inferior (“lower”) head of lateral pterygoid
O/I: Lateral pterygoid plate into neck of condyle
A: Protrusive and mediotrusive movements

Question 19

Suprahyoid muscles

Originate where
Insert where
Action (what muscle are they synergistic with)

Answer 19

Digastric, geniohyoid, and mylohyoid

Digastric anterior belly goes from mandible at midline to hyoid, and then posterior belly from mastoid notch to hyoid

Geniohyoid: Genial tubercle to hyoid

Mylohyoid: Mylohyoid ridge to hyoid

Action: Open the mandible (synergic with inferior belly of lateral pterygoid)

Question 20

Steps for swallowing?
- Voluntary (1)
- Involuntary phase (2)

Answer 20

1. Oral phase (voluntary) - “Preparing the bolus”
   - Tongue collects food into bolus, lips seal tightly, soft palate elevates to prevent food from entering nasal cavity
2. Pharyngeal phase (involuntary) - “Protecting the Airway” - soft palate elevates, epiglottis covers down airway, tongue pushes bolus back, pharyngeal constrictor muscles contract (propelling food down), upper esophageal sphincter relaxes (food enters esophagus)
3. Esophageal phase - bolus moves downward via peristalsis

Question 21

Muscles of facial expression - What does buccinator and zygomatic major do?

Answer 21

Compress cheek, create buccal furrow

Elevates corner of mouth, smile

Question 22

Muscles of facial expression - What do depressor labii inferiors and levator labii superiors do?

Answer 22

Depress lip

Elevate upper lip

Question 23

Muscles of facial expression - What do orbicular oris and risorius do?

What about zygomaticus minor?

Answer 23

Pucker lips

Smile, elevate corner of mouth

Raise upper lip

Question 24

Soft palate - Sounds?

Answer 24

Nasal sounds [m/n/ng] as in [swimming]

Question 25

Plosives - Sounds?

Answer 25

[b/p] as in [ball/paw]

Question 26

Fricatives - Sounds? Anatomic movement?

Answer 26

[f/v] as in [frank/victor] Incisors must touch "wet-dry line" of lower lip lower lip to upper tooth

Question 27

Sibilants (considered a subset of fricative sounds)

Answer 27

[s] or [ch/ee] as in cheese Distance between incisal is 1 mm, typically called "closest speaking space"

Question 28

Lingual-dental sounds? Anatomic movement?

Answer 28

[th] Tip of tongue touch lingual of maxillary incisors and alveolar ridge

Question 29

Facial nerve (CN VII) innervates what muscles (2) and provides what parafunctions (2)?

Answer 29

1. Facial expression (incl. buccinator) 2. Posterior belly of digastric and stapedius 3. Taste from anterior 2/3 of tongue 4. Secretomotor innervation to salivary and lacrimal glands except parotid (which gets parasympathetic from glossopharyngeal nerve)

Question 30

Glosspharyngeal nerve (CN IX) innervates what parafunctions (2) and what motor (1)?

Answer 30

1. Taste from posterior 1/3 of tongue 2. Provides secretomotor innervation to parotid gland 3. Motor to stylopharygeous

Question 31

What nerve provides motor to muscles of the tongue except one?

Answer 31

Hypoglossal (12), except palatoglossus which is Vagus (X)

Question 32

Four intrinsic muscles and four extrinsic muscles of the tongue?

Answer 32

Superior longitudinal, inferior longitudinal, transverse, vertical Genioglossus, hyoglossus, styloglossus, palatoglossus

Question 33

Trigeminal nerve innervates what muscles (8)

Answer 33

Masseter, temporalis, medial pterygoid, lateral pterygoid Digastric (ant belly), mylohyoid Tensor veli palatini, tensor typmpani

Question 34

Accessory nerve (XI) controls what two head and neck muscles?

Answer 34

1. Sternocleidomastoid 2. Trapezius

Question 35

After how many mm of rotation, does translation occur? Who first published on this? Does translation of the condyle-disk assembly occur in the upper or lower joint compartment?

Answer 35

1. After 20 mm 2. McCollum and Stuart 3. Upper joint compartment

Question 36

Who published that 10% of the population have MI at CO?

Answer 36

Ramjord and Ash

Question 37

Which muscle of mastication is attributed to the beginning of the power stroke?

Answer 37

Medial pterygoid

Question 38

What class lever system is the masticatory system? What are each of the three components? Can you give examples of the other two types?

Answer 38

Class 3 ("FEL") - Effort is between the fulcrum and load Fulcrum: TMJ Effort: Muscles of mastication Load: Food placed on teeth Class I: LFE - Seesaw Class 2: ELF - Wheelbarrow

Question 39

What muscle is acknowledged as the most important muscle responsible for retrusion?

Answer 39

Posterior part of temporalis

Question 40

What's the most common disorder involving the TMJ disk?

Answer 40

Internal joint derangement or anteriorly displaced disk (posterior band displaced anteriorly w/ or w/o reduction)

Question 41

Patients w/ anterior displaced disk w/o reduction may progress into what? If acute, the displacement results in what two things? Which side does the mandible deviate to?

Answer 41

1. Osteoarthritis 2. Pain and closed lock (limited condylar translation) 3. Towards affected side

Question 42

What non-inflammatory disorder can affect the TMJ? Is there an agreement as to the causality between this disorder and TMJ disk displacement? Most common symptom?

Answer 42

Osteoarthritis - Signs of degeneration of the fibrocartilage, as a failure of the remodeling process No agreement between osteoarthritic changes and TMJ disk displacement Pain upon palpation of the affected joint and during function

Question 43

Most common inflammatory disorders of TMJ (3) Most common symptom?

Answer 43

1. Capsulitis 2. Synovitis 3. Polyarthritides (from rheumatoid arthritis, gout, lupus, etc) Symptom: Pain, exacerbated by TMJ loading

Question 44

Biologic width - Modern interpretations - What did Vacek 1994 find? - Ingber 1977 - "biologic width violation"? - Lipski 2018 - Does every patient need crown lengthening? - Becker & Ochsenbein 1992 - Thick gingival biotypes?

Answer 44

Vacek - Biologic width 2-4 mm Ingber - Restorative margins too close caused inflammation, bone resorption, gingival recession Lipski 2018 - Some patients naturally adapt to sub gingival margins w/o significant inflammation Becker & Oshsenbein - Thick biotypes develop deep pockets whereas thin develop recession when Biologic width violated

Question 45

Based on McNamara's rhesus monkey and Gibbs and Mahan research 1. Clenching occurs when Superior belly or inferior belly of lateral pterygoid is contracted maximally? 2. Protrusive movement with incisal guidance? SLP or ILP

Answer 45

1. SLP 2. ILP

Question 46

Which muscle is active (EMG-wise) in suspending the mandible? Which muscles active (EMG-wise) in opening the mandible? (2)

Answer 46

Lateral pterygoid - Upper head (minimally though - it’s not as active as other muscles during their action) Suprahyoid (rotation) and Lateral pterygoid (Lower head) (translation)

Question 47

Which muscles are active during clenching? (3) Which muscles are active during grinding? (2)

Answer 47

Clenching: Masseter, temporalis, and lateral pterygoid (upper head) Grinding: Temporalis and lateral pterygoid (lower head - protrudes mandible forward)

Question 48

TMJ Exam - Walk through "I follow a systematic approach involving history and a clinical exam including range of motion, joint sounds, and palpation."

Answer 48

I follow a systematic approach involving history and a clinical exam including range of motion, joint sounds, and palpation. 1. History (chief complaints, pain soreness, any joint sounds, jaw locks, trouble opening wide, clench/grind, history of trauma, med history like arthritis) 2. Range of Motion - Observe deviation - Max opening (40-55 incisors). If limited, passive or active - Lateral movement (8-12 mm) -Protrusive movement (8-10 mm) 3. joint sounds (fingers over poles). Note sounds (when like early/late, reciprocal click on open/close) 4. Muscle palpation and tenderness. Temporalis, masseter, med/lat pterygoids (impossible), accessory muscles (SCM and trapezius if neck pain) 5. Joint palpation for tenderness during open/close

Question 49

Crepitus during protrusion indicates what? Crepitus during opening movement indicates what? Difference between osteoarthosis and osteoarthritis

Answer 49

Changes in the temporal joint surface Changes in the condylar surface Osteoarthosis (painless) or osteoarthritis (pain)