Question 1

In what plane and axis does mandibular elevation and depression occur?&#10;A)Sagittal plane around a medial-lateral (frontal) axis&#10;B)Transverse plane around a vertical axis&#10;C)Frontal plane around a sagittal axis&#10;D)Transverse plane around a medial-lateral (frontal) axis

Accepted Answer

Mandibular elevation and depression occur in the sagittal plane around a medial-lateral (frontal) axis. This means that the movement is up and down, with the axis running from side to side through the jaw.

Question 2

What arthrokinematics occur during mandibular protrusion?&#10;A)Disc-condyle complex glides anteriorly&#10;B)Condyles roll anteriorly, and condyles and disc glide posteriorly&#10;C)Disc-condyle complex glides posteriorly&#10;D)Condyles roll posteriorly, and condyles and disc glide anteriorly

Accepted Answer

During mandibular protrusion, the disc-condyle complex glides anteriorly on the articular eminence of the temporal bone, facilitating the forward movement of the jaw.

Question 3

Which of the following muscle groups contracts to elevate the temporomandibular joint?&#10;A)Concentric contraction of bilateral digastric and inferior lateral pterygoid muscles&#10;B)Bilateral contraction of masseter and medial and lateral pterygoid muscles&#10;C)Concentric contraction of bilateral masseter, temporalis, and medial pterygoid muscles&#10;D)Bilateral contraction of posterior fibers of the temporalis muscle and anterior portion of digastric muscle

Accepted Answer

The temporomandibular joint is elevated by the concentric contraction of the masseter, temporalis, and medial pterygoid muscles, which are responsible for closing the jaw.

Question 4

What are the primary muscles of mastication?&#10;A)Masseter, anterior and posterior portions of the digastric muscle&#10;B)Suprahyoid muscle group, masseter&#10;C)Temporalis, masseter, medial and lateral pterygoids&#10;D)Masseter, digastric, medial and lateral pterygoids

Accepted Answer

The primary muscles of mastication are the temporalis, masseter, and medial and lateral pterygoids. The masseter is responsible for elevating the mandible, while the temporalis and pterygoids aid in the movement of the mandible in various directions during chewing. The suprahyoid muscle group and digastric muscles are not primary muscles of mastication, but rather muscles involved in swallowing and opening/closing of the jaw, respectively.

Question 5

Which of the following muscle groups contracts to protrude the temporomandibular joint?&#10;A)Concentric contraction of bilateral digastric and inferior lateral pterygoid muscles&#10;B)Bilateral contraction of masseter and medial and lateral pterygoid muscles&#10;C)Concentric contraction of bilateral masseter, temporalis, and medial pterygoid muscles&#10;D)Bilateral contraction of posterior fibers of the temporalis muscle and anterior portion of digastric muscle

Accepted Answer

The masseter and medial and lateral pterygoid muscles are the main muscles responsible for protruding the temporomandibular joint. The digastric and temporalis muscles contribute to jaw opening and closing, but not protrusion. The posterior fibers of the temporalis muscle and anterior portion of digastric muscle also do not contribute significantly to protrusion.

Question 6

What are the attachments of the disc located in the temporomandibular joint?&#10;A)Anterior to joint capsule and lateral pterygoid muscle, posterior to connective tissue&#10;B)Lateral to lateral pterygoid muscle, medial to medial pterygoid muscle&#10;C)Anterior to joint capsule and medial pterygoid muscle, posterior to connective tissue&#10;D)Lateral to joint capsule, medial to connective tissue

Accepted Answer

The disc of the temporomandibular joint (TMJ) is attached anteriorly to the joint capsule and the superior head of the lateral pterygoid muscle, and posteriorly to connective tissue that includes the retrodiscal pad, making option A correct.

Question 7

Which of the following statements BEST describes how the temporomandibular joint surface is different from other synovial joints in the body?&#10;A)Joint surface covered with hyaline cartilage that resists repetitive stresses and can repair itself&#10;B)Joint surface covered with hyaline cartilage that undergoes stress and cannot repair itself&#10;C)Joint surface covered with dense fibrocartilage that resists repetitive stresses and can repair itself&#10;D)Joint surface covered with dense fibrocartilage that undergoes stress and cannot repair itself

Accepted Answer

The temporomandibular joint (TMJ) surface is unique among synovial joints because it is covered with dense fibrocartilage, not hyaline cartilage. This type of cartilage is better suited to resist the repetitive stresses the TMJ undergoes and has some capacity for repair, unlike hyaline cartilage which has limited repair capabilities.

Question 8

What is the typical range of motion for mandibular lateral excursion?&#10;A)1-5 mm&#10;B)8-11 mm&#10;C)15-20 mm&#10;D)30-40 mm

Accepted Answer

The typical range of motion for mandibular lateral excursion is 8-11 mm. This movement refers to the side-to-side movement of the lower jaw, which is important for chewing and grinding food.

Question 9

Which of the following statements BEST describes the function of the temporomandibular joint disc?&#10;A)The upper surface and temporal bone form a hinge joint&#10;B)Increases joint stability, decreases joint stress&#10;C)The lower surface and mandibular condyle function as a gliding joint&#10;D)Is able to repair itself when injured

Accepted Answer

The temporomandibular joint disc functions to increase joint stability and decrease joint stress by distributing the load of movement across the joint surface. It acts like a shock absorber and helps to prevent joint damage or injury. While there is some gliding movement between the lower surface of the disc and the mandibular condyle, this is not the primary function of the disc. The joint is also not able to repair itself when injured, so option D is incorrect. The upper surface of the disc and temporal bone do form a hinge joint, but this is not the primary function of the disc. Therefore, option A is also incorrect.

Question 10

What is the function of the temporomandibular ligament?&#10;A)Limits mandibular elevation&#10;B)Limits mandibular protrusion&#10;C)Limits mandibular lateral excursion&#10;D)Limits mandibular depression

Accepted Answer

The temporomandibular ligament primarily functions to limit mandibular depression, which is the downward movement of the jaw. This helps in preventing excessive opening of the mouth.

Question 11

What are the cardinal signs of temporomandibular joint dysfunction?&#10;A)Joint pain, noise, limited range of motion&#10;B)Joint swelling, pain&#10;C)Joint pain, muscle weakness&#10;D)Joint pain, bruising, limited range of motion

Accepted Answer

The answer of What are the cardinal signs of temporomandibular...

Question 12

What arthrokinematics occur during mandibular depression?&#10;A)Condyles roll posteriorly, and condyles and disc glide anteriorly&#10;B)Condyles roll anteriorly, and condyles and disc glide posteriorly&#10;C)Condyles roll anteriorly, and condyles and disc glide anteriorly&#10;D)Condyles roll posteriorly, and condyles and disc glide posteriorly

Accepted Answer

The answer of What arthrokinematics occur during mandibular depression?&#10;A)Condyles roll...

Question 13

What is the typical range of motion for mandibular depression?&#10;A)10-20 mm&#10;B)40-50 mm&#10;C)20-30 mm&#10;D)50-100 mm

Accepted Answer

The answer of What is the typical range of motion...

Deck 7: Structure and Function of the Temporomandibular Joint