TMJ-pp2

Question 1

What fixed and mobile components make up the TMJ? What type of joint is the TMJ?

Answer 1

Fixed (cranial) components: Mandibular (glenoid) Fossa & the Articular Tubercle (eminence)
Mobile comp: Head of the Mandibular Condyle
These components make up the SYNOVIAL joint that is the TMJ

Question 2

What type of connective tissue is found in the articular disc (meniscus) of the TMJ?

Answer 2

Articular connective tissue

Question 3

What are three movements of the mandibular condyle at the TMJ while opening, closing mouth and chewing food?

Answer 3

1. Rotation (hinging)
2. Translation (gliding) - protrusion and retrusion
3. Lateral excursion

Question 4

Describe lateral excursion of the mandibular condyle. What are the two opposite condyles referred to as during this process? What side of the mouth is referred to as the “Working” side during mastication?

Answer 4

Lateral excursion of the mandible is when the “swinging condyle”protrudes forward and to the side around the axis of rotation of the “resting condyle” which remains in place in the TMJ & rotates. The movement shifts the mandible to one side of the mouth or the other and is critical in grinding the food. The side of the mouth that the mandible shifts towards is referred to as the “Working” side.

Question 5

What is the origin, insertion, and function of the STYLOMANDIBULAR Ligament

Answer 5

Ori: Styloid Process
Ins: Angle of Mandible
Fun: Suspends mandible from underside of the cranium very important

Question 6

Where does the SPHENOMANDIBULAR Ligament attach? Purpose?

Answer 6

Attaches to the LINGULA of the mandible. What determines lingula size. Maintains Condylar Head position w/in the middle of the Mandibular Foramen

Question 7

Superior and Inferior compartment of the TMJ seperate what from what, creating what type of joint?

Answer 7

Superior Component: Separates the meniscus from the articular disk of the temporal bone creating a GLIDING (Arthrodial) Joint
Inferior Component: Separates the condyle from the inferior surface of the meniscus creating a HINGE (Ginglymus) Joint

Question 8

When gaping the jaw. The jaw is translated anteriorly, shifting the axis of rotation from the inferior surface of the meniscus to the neurovascular hub (intermediate surface), where further hinging occurs to fully open the mouth. Why is the jaw translated anteriorly in the middle step?

Answer 8

To reduce strain on the Inferior Alveolar NVB

Question 9

What 2 feature’s limit the hinging action of the TMJ to prevent dislocation?

Answer 9

1. Temporomandibular (lateral) ligament

2. Parotid gland

Question 10

Why do the condyle and meniscus translate downward and forward TOGETHER during opening of the mouth? 2 reasons…

Answer 10

1. B/c the disc is more firmly attached to the condyle than it is to the fossa
2. B/c both are attached to the lateral Pterygoid, the only muscle of mastication contributing to depression of the mandible

Question 11

What innervates the TMJ?

Answer 11

Branches of the CNV3- the mandibular division of the trigeminal nerve