TMJ and MOM

Question 1

What makes up the TMJ?

Answer 1

Manidbular fossa of the temporal bone and condylar process of the mandible

Question 2

What type of cartilage is found within the TMJ?

Answer 2

Fibrocartilage

Question 3

Which muscles are responsible for elevation of the mandible?

Answer 3

Temporalis, Masseter and Medial Pterygoid.

Question 4

Which muscle are responsible for depression of the mandible?

Answer 4

Lateral pterygoid, suprahyoid and infra hyoid muscles.

Question 5

Which muscles are responsible for Protrusion of the mandible?

Answer 5

Masseter, Lateral Pterygoid and medial Pterygoid.

Question 6

Which muscles are responsible for retrusion of the mandible?

Answer 6

Temporalis.

Question 7

Which muscles are responsible for lateral movement of the mandible?

Answer 7

Temporalis on the same side and pterygoids on the opposite side. Masseter

Question 8

Origin and Insertion of Temporalis

Answer 8

Origin- Temporal Fossa
Insertion- coronoid process of mandible and anterior border of ramus.

Question 9

Origin and Insertion of Masseter

Answer 9

Origin- Maxillary process of the zygomatic arch and anterior 2/3 of inferior border of zygomatic arch
Insertion- Angle and lateral surface of the ramus of the mandible

Question 10

Origin and insertion of the Medial Pterygoid

Answer 10

Origin- Medial surface of the lateral pterygoid plate and maxillary tuberosity
Insertion- medial surface of the ramus and angle of the mandible.

Question 11

What nerve supplies the TMJ?

Answer 11

Auriculotemporal nerve

Question 12

Origin and insertion of the lateral pterygoid.

Answer 12

Origin- lateral surface of the lateral pterygoid plate
Insertion- anterior border of the condyle and intra-articular disc via two independent heads.

Question 13

How would you examine master and temporalis?

Answer 13

Place hands over the region of the muscles and ask the patient to clench.
Feel for hypertrophy of the muscles on both sides and ask the patient if it is tender whilst clenching.

Question 14

How would you examine the lateral pterygoid?

Answer 14

Cannot be palpated intra-orally.

Best examined in response to resisted movement.
- Ask the patient to deviate the mandible to one side and resist the movement by pushing it to the opposite side.
- Ask the patient if this feels tender.

Question 15

How would you examine the medial pterygoid?

Answer 15

Cannot reliably palpate or examine this muscle.

Question 16

If a patient could not open their mouth after having an IDB, what is this called and what muscle would be affected?

Answer 16

Trismus- medial pterygoid.

Question 17

Which teeth generate the greatest biting force?

Answer 17

1st molars.

Question 18

Why do the molar teeth generate the greatest bighting force compared to other teeth?

Answer 18

Position of these teeth are nearer the TMJ and MOM- the force generating the muscles and the fulcrum.
Large root surface area- PDL support.

Question 19

Which muscles are the suprahyoid muscles?

Answer 19

Digastric
Mylohyoid
Geniohyoid
Stylohyoid.

Question 20

What muscles are the infrhyoid muscles?

Answer 20

Sternohyoid
Omohyoid
Thyrohyoid
Sternothyroid