TMJ And Infratemporal Fossa

Question 1

What type of joint is the TMJ?

Answer 1

Hinge-type synovial

Question 2

What two bones articulate at the TMJ?

Answer 2

Articulate tubercle of the temporal bone and condyle of the mandible and the mandibular fossa

Question 3

What does the articular disc divide the TMJ into?

Answer 3

Sup and inf compartments

Question 4

Is the joint capsule strong or loose? Why? What ligaments support it?

Answer 4

Loose- so it is moveable.
Lat ligament (TMJ ligament)
Stylomandibular ligament
Sphenomadibular ligament

Question 5

Which muscles elevate the mandible?

Answer 5

Temporal, masseter, med pterygoid

Question 6

Which muscles depress the mandible?

Answer 6

Mainly gravity but lat pterygoid and supra/infrahyoid

Question 7

Which muscles protrude the mandible?

Answer 7

Lat pterygoid

Question 8

Which muscle does retrusion of the mandible?

Answer 8

Temporal

Question 9

Which muscles laterally move the mandible?

Answer 9

Temporal, pterygoid (of opposite side)

Question 10

How is the TMJ usually dislocated? Where does the head of the mandible go?

Answer 10

Blow to side of chin when mouth open. -> ant dislocation of same side
Head of mandible -> ant to articular tubercle

Question 11

Name 3 causes of pain around the TMJ. One social and psychological cause of them

Answer 11

Grinding (bruxism), osteoarthritis of TMJ, inter-articular disc derangement
Smoking, anxiety

Question 12

What is the infratemporal fossa?

Answer 12

Irregular shaped deep space inf to zygomatic arch and deep to ramus of mandible

Question 13

What are the boarders of the infratemporal fossa?

Answer 13

Sup- inf greater wing of sphenoid 
Inf- med pterygoid muscle at mandible attachment
Ant- post maxilla
Post- temporal 
Med- lat pterygoid plate of spheroid
Lat- ramus of mandible

Question 14

What is the contents of the infratemporal fossa?

Answer 14

3 muscles- temporal (inf part), lat and med pterygoid
Maxillary artery
Pterygoid venous plexus and maxillary vein
6 nerves- mandibular, inf alveolar, lingual, buccal, chorda tympani and otic ganglion

Question 15

What does the pterygoid venous plexus communicate with?

Answer 15

Cavernous sinus

Question 16

What does the inf alveolar nerve continue as?

Answer 16

Mental nerve once it exits via mental foramen

Question 17

Where can infection in the infratemporal fossa spread to? Which people might they be seen in?

Answer 17

Cavernous sinus thrombosis risk due to pterygoid plexus communication with cavernous sinus
Isolated infections e.g diabetics

Question 18

What is the fossa useful for?

Answer 18

Nerve block