TMJ and Muscles

Question 1

What are the three major parts of the TMJ?

Answer 1

Mandibular condyle, articular fossa and eminence (of the temporal bone), and articular disc

Question 2

What are the four ligaments of the TMJ?

Answer 2

Fibrous capsule (capsular ligament), lateral ligament, stylomandibular ligament, sphenomandibular ligament

Question 3

What are the four muscles of mastication?

Answer 3

Masseter, temporalis, medial pterygoid, and lateral pterygoid,

Question 4

What is the function of the masseter muscle?

Answer 4

To elevate mandible (close teeth together)

Question 5

What is the origin and insertion of the masseter muscle?

Answer 5

Origin: zygomatic arch
Insertion: lateral surface of rami and angle of mandible

Question 6

What is the function of the temporalis muscle?

Answer 6

To elevate and position (retrude) mandible

Question 7

The anterior part of the temporalis muscle generally moves the mandible in what way?

Answer 7

Elevates the mandible (closes teeth), these are mostly vertical fibers

Question 8

The posterior part of the temporalis muscle generally moves the mandible in what way?

Answer 8

Retrude the mandible, these fibers are more horizontal

Question 9

Where is the origin and insertion of the temporalis muscle?

Answer 9

Origin: temporal fossa on cranium
Insertion: coronoid fossa, anterior border of ramus, and temporal crest

Question 10

What is the function of the medial pterygoid muscle?

Answer 10

To elevate mandible (close teeth together)

Question 11

What is the origin and insertion of the medial pterygoid muscle?

Answer 11

Origin: pterygoid fossa (sphenoid)
Insertion: medial angle of mandible

Question 12

What is the function of the lateral pterygoid muscle?

Answer 12

One alone moves mandible laterally, together they protrude and depress mandible

Question 13

What is the origin and insertion of the lateral pterygoid muscle?

Answer 13

Origin: lateral pterygoid plate (sphenoid) and greater wing
Insertion: pterygoid fovea (condylar process) and anterior part of articular disc

Question 14

What are the three suprahyoid muscles?

Answer 14

Geniohyloid, mylohyoid, and digastric

Question 15

What are the two infrahyoids?

Answer 15

Omohyoid and sternohyoid

Question 16

Together the suprahyoids and infrahyoids move the mandible in what way?

Answer 16

Open mouth and depress mandible

Question 17

What is the muscle that immediately surrounds the lips?

Answer 17

Orbicularis oris

Question 18

What are the three muscles of the upper lip?

Answer 18

Zygomaticus, levator labii superior, levator anguli oris

Question 19

What are the three muscles of the lower lip?

Answer 19

Depressor labii inferior, depressor anguli oris, mentalis

Question 20

What muscles are involved in elevation of the mandible?

Answer 20

Masseters, medial pterygoids, temporalis (anterior vertical and middle fibers)

Question 21

What muscles are involved in depression of the mandible?

Answer 21

Supra- and infra hyoids together, and both lateral pterygoids

Question 22

What muscles are involved in the retrusion of the mandible?

Answer 22

Temporalis (posterior horizontal fibers) and suprahyoids (with help from infrahyoids)

Question 23

What muscle is involved in protrusion of the mandible?

Answer 23

Both lateral pterygoids together

Question 24

What muscle is involved in lateral excursion of the mandible?

Answer 24

Right lateral pterygoid moves the mandible to the left and left lateral pterygoid moves the mandible to the right

Question 25

What cranial nerve supplies the muscles of mastication?

Answer 25

Trigeminal (CN V) division III mandibular branch

Question 26

What cranial nerve supplies the muscles of facial expression?

Answer 26

Facial (cranial nerve VII)