Tempro – mandibular Joint

Question 1

what is the origin and insertion of the lateral pterygoid

Answer 1

origin:Upper: greater wing of sphenoid.
Lower: lateral pterygoid plate (lateral surface).

insertion: Depression in the neck of mandible (pterygoid fovea), capsule & articular disc of tempero - mandibular joint (TMJ).

Question 2

what is the nerve supply of lateral pterygoid

Answer 2

Nerve supply: nerve to lateral pterygoid which is a branch from anterior division of mandibular nerve.

Question 3

what action does the lateral pterygoid perform

Answer 3

Protrusion of mandible (mouth opener).

Chewing movements with medial pterygoid.

Question 4

what is the origin and insertion of the medial pterygoid

Answer 4

origin:Deep: Lateral pterygoid plate (medial surface).
Superficial: Tuberosity of maxilla.

insertion:Medial surface of ramus & angle of mandible.

Question 5

what is the nerve supply of the medial pterygoid

Answer 5

Nerve to medial pterygoid ,branch from trunk of mandibular nerve.

Question 6

what is the action of the medial pterygoid

Answer 6

Elevation of mandible

Chewing movements of mandible with lateral pterygoid muscle.

Question 7

what is the origin and insertion of the temporalis

Answer 7

Origin: Floor of the temporal fossa.
Insertion: coronoid process of the mandible.

Question 8

what is the action of the temporalis

Answer 8

Elevates (vertical fibers, closes mouth) and horizontal fibers retracts the mandible.

Question 9

what is the nerve supply of the tempporalis

Answer 9

temporal nerves

Question 10

what is the origin and insertion of the masseter muscle

Answer 10

Origin: Inferior border of the zygomatic arch.
Insertion: Lateral surface of the ramus of the mandible.

Question 11

what is the action of the masseter muscle

Answer 11

Action: Elevates the mandible (closes the mouth).

Question 12

what nerve supplies the masseter muscle

Answer 12

Nerve supply: Masseteric nerves.

Question 13

what structures stabilize the joint

Answer 13

Fibrous capsule.
Lateral ligament.
Spheno - mandibular ligament.
Stylo - mandibular ligaments.

Question 14

what are the insertion points of the fibrous capsule

Answer 14

Above: to the articular tubercle and the margins of the mandibular fossa.
Below: to the mandibular neck.

Question 15

what are the insertion points of the lateral temporo- mandibular ligament

Answer 15

Site: lateral to the fibrous capsule.

Question 16

what is the insertion point of the spheno mandibular ligament

Answer 16

Attachments: above to spine of sphenoid, below to the lingula of the mandible.

Question 17

what is the insertion points of the stylo mandibular ligament

Answer 17

Attachments: above to the tip of the styloid process, below to the angle and posterior border of the mandible

Question 18

what kind of cartilage is the articular disk made of

Answer 18

It is a fibrocartilage disc which divides the joint cavity into upper and lower parts.

Question 19

what is the shape of the articular disc

Answer 19

Shape: its upper surface is concav-convex to fit the articular tubercle and mandibular fossa respectively. Its lower surface is concave for the head of the mandible.

Question 20

which muscles are used when protrusion of the mandible occurs

Answer 20

Protrusion: Action of lateral pterygoid muscles of both sides simultaneously.
The articular disc glide forwards in upper compartment.

Question 21

which muscles are used for retraction of the mandible

Answer 21

Retraction: Posterior fibers of the temporalis muscle.

The articular disc glide backwards in upper compartment

Question 22

which muscles are used for elevation of the mandible

Answer 22

Elevation: Masseter, anterior fibers of temporalis and medial pterygoid muscles.

Question 23

which muscles are used for depression of the mandible

Answer 23

Depression: Lateral
pterygoids assisted by
myelohyoid and digastric muscles.

Question 24

what is the blood and nerve supply to this area

Answer 24

Blood Supply: Superficial temporal artery.

Nerve Supply: Auriculo - temporal nerve.

Question 25

what are the most common ways dislocation of the mandibles occurs

Answer 25

Can occur via a blow to the side of the face, yawning, or taking a large bite.

Question 26

how does dislocation of the mandible occur

Answer 26

It takes place in forward direction.

The head of the mandible slips into infra - temporal fossa during wide opening of mouth by lateral pterygoid muscle.

Question 27

what is the process of relocating the mandible

Answer 27

The thumbs are placed upon the lower molars intra- orally, with the fingers wrapped externally around the mandibles.
With the patient positioned with the mandible below the level of the practitioner’s elbows, apply firm, slow, and steady pressure in a downward and posterior direction.