Infratemporal Fossa and TMJ

Question 1

Describe depression of the mandible and the muscles involved

Answer 1

The head of the mandible rotates on the undersurface of the articular disc and the mandible is pulled forward

Lateral pterygoid, digastric, geniohyoid, mylohyoid and gravity

Question 2

What is the chorda tympani?

Answer 2

A branch of the facial nerve
Carries afferent taste signals from anterior aspect of tongue
Joins the lingual nerve into the oral cavity

Question 3

How does the mandibular division of the trigeminal (CN V3) nerve reach the infratemporal fossa?

Answer 3

Passes through the foramen ovale

Question 4

What is the innervation of the medial and lateral pterygoids?

Answer 4

Mandibular division of Trigeminal nerve (CN V3)

Question 5

Describe lateral chewing and the muscles involved

Answer 5

Protrusion and Retrusion combined

Pterygoid muscles

Question 6

What divides the joint cavity of the TMJ?

Answer 6

Fibrous articular disc

Question 7

What are the boundaries of the infratemporal fossa?

Answer 7

Anterior = posterior surface of the maxilla
Posterior = styloid process
Superior = infratemporal surface of the greater wing of sphenoid
Medial = lateral pterygoid plate
Lateral = ramus of mandible

Question 8

Describe protrusion of the mandible and the muscles involved

Answer 8

Articular disc and the head of the mandible move forward. Movement is in the upper part of the cavity

Lateral pterygoid (medial pterygoid assists)

Question 9

What is the infratemporal fossa?

Answer 9

Space beneath the base of the skull - between the skull and the ramus of the mandible

Question 10

Between the heads of which muscles does the maxillary artery pass between?

Answer 10

The 2 heads of lateral pterygoid

Question 11

What are the branches of the pterygopalatine branch of the maxillary artery?

Answer 11

Posterior superior alveolar
Infraorbital
Artery to the pterygoid canal
Pharyngeal
Palatine 
Sphenopalatine

Question 12

What type of joint is the TMJ?

Answer 12

Synovial joint

Question 13

Describe retrusion of the mandible and muscles involved

Answer 13

Articular disc and head of mandible are moved back into the mandibular fossa

Posterior fibres of temporalis

Question 14

What is the contents of the infratemporal fossa? (6)

Answer 14

Lateral and Medial pterygoid
Mandibular division of the trigeminal (CN V3) and branches
Maxillary artery and branches
Pterygoid venous plexus
Chorda Tympani
Otic ganglion

Question 15

What does the pterygoid venous plexus communicate with?

Answer 15

Cavernous sinus and facial veins

This is a route for infection

Question 16

What is the function of the disc of the TMJ

Answer 16

Increases the congruency of the articular surfaces

Question 17

What are the 3 parts of the maxillary artery?

Answer 17

Mandibular
Pterygoid
Pterygopalatine

Question 18

Describe elevation of the mandible and the muscles involved

Answer 18

The head of the mandible and the disc move backwards and the head rotates on the lower surface of the disc

Temporalis, Masseter, Medial Pterygoid

Question 19

Where is the TMJ located?

Answer 19

Between the head of the mandible and mandibular fossa and articular tubercle on the squamous part of the temporal bone

Question 20

What are the posterior divisions of the mandibular division of the Trigeminal nerve (CN V3)?

Answer 20

Lingual (which is joined by chorda tympani)
Inferior alveolar
Mylohyoid
Auriculotemporal

Question 21

What strengthns the joint capsule of the TMJ?

Answer 21

Laterally by the Temporomandibular ligament

Medially by the Sphenomandibular and Stylomandibular ligament

Question 22

What is the otic ganglion?

Answer 22

A parasympathetic ganglion located at the mouth of the foramen ovale in the infratemporal fossa.
It recieves parasympathetic fibres from glossopharyngeal nerve CN IX
Supplies secretomotor innervation to the parotid gland

Question 23

What are the anterior divisions of the mandibular branch of trigeminal (CN V3)?

Answer 23

2x deep temporal
Masseteric
Nerve to lateral pterygoid
Buccal