Infratemporal Fossa

Question 1

What is a temporal fossa?

Answer 1

Bony constriction posterior to the orbit and superior to the zygomatic arch. It is filled with temporalis muscle.

Question 2

What is an infratemporal fossa?

Answer 2

Deep and inferior to the temporal fossa, lateral to the later pterygoid plate. It contains TMJ, distal portion of temporalis muscle, medial/lateral pterygoid muscles, maxillary artery, pterygoid venous plexus, mandibular division of trigeminal.

Question 3

What is the pterygopalatine fossa?

Answer 3

Deeper, located between the anterior surface of the pterygoid plates of the sphenoid bone, and the posterior wall of the maxilla. It is bounded medially by the vertical perpendicular plate of the palatine bone, laterally through the pterygomaxillary fissure. It is the realm of the maxillary division of the trigeminal and pterygopalatine ganglion.

Question 4

What is the lateral boundary of the infratemporal fossa?

Answer 4

Ascending ramus of mandible

Question 5

What is the medial boundary of the infratemporal fossa?

Answer 5

Lateral pterygoid plate

Question 6

What is the anterior boundary of the infratemporal fossa?

Answer 6

The posterior maxilla

Question 7

What is the posterior boundary of the infratemporal fossa?

Answer 7

Tympanic-mastoid-styloid portions of temporal bone

Question 8

What is the inferior boundary of the infratemporal fossa?

Answer 8

Where the medial pterygoid muscle attaches to the gonial angle

Question 9

What is the superior boundary of the infratemporal fossa?

Answer 9

Greater wing of the sphenoid and temporalis muscle

Question 10

What are the artery components of the infratemporal fossa?

Answer 10

Maxillary artery (branch of external carotid) –> “mandibular” portion (deep auricular, anterior tympanic, middle and accessory meningeal, and inferior alveolar), “pterygoid” portion (masticatory muscles branches)

third branch of maxillary artery goes into pterygopalatine fossa

Question 11

What are the venous components of the infratemporal fossa?

Answer 11

Pterygoid plexus of veins (drains maxillary artery)

connects directly to emissary veins from cavernous sinus, inferior ophthalmic vein, and deep facial veins

Question 12

What are the nerve contents of the infratemporal fossa?

Answer 12

V3 (mandibular, from the foramen ovale) –> branches to lingual nerve (with chorda tympani from CN VII), inferior alveolar nerve, buccal nerve, motor branches to masticatory muscles, and auriclotemporal nerve (conveys parotid gland IX parasympathetic secretomotor fibers in lesser petrosal nerve that synapsed in the otic ganglion)

Question 13

What is the structure of the temporomandibular joint (TMJ)?

Answer 13

A synovial joint separated by a fibrocartilaginous disc

Question 14

What ligaments are around the TMJ?

Answer 14

Temporomandibular (lateral) ligament, sphenomandibular ligament, stylomandibular ligament

Question 15

What is the function of the TMJ?

Answer 15

It is a modified hinge joint - predominantly hinge movements in the lower compartment, but also some gliding actions

Question 16

What are the constraints on mandibular movements?

Answer 16

Sphenomandibular ligament and stylomandibular ligament support the mandible (ultimately they don’t restrict motion much)

Question 17

How does the mandible develop?

Answer 17

Develops via intramembranous ossification of branchial arch I mesenchyme around the first arch cartilaginous rod

Question 18

What are the attachments of the temporalis muscle?

Answer 18

Temporal and parietal bones to coronoid process

Question 19

What is the function of the temporalis muscle?

Answer 19

Elevation and retraction

Question 20

What are the attachments of the masseter muscle?

Answer 20

Zygomatic arch to ramus and angle of mandible (superficial and deep part)

Question 21

What is the function of the masseter muscle?

Answer 21

Elevation, protraction, lateral excursion

Question 22

What are the attachments of the medial pterygoid?

Answer 22

Arises between pterygoid plates, runs like masseter but deep to ramus (forming pterygo-masseteric sling)

Question 23

What are the functions of the medial pterygoid?

Answer 23

Elevation, protraction, contralateral excursion

Question 24

What are the attachments of the lateral pterygoid?

Answer 24

Lateral pterygoid plate and infratemporal fossa to neck of condyle and articular disc

It has a superior and inferior part

Question 25

What are the functions of the lateral pterygoid?

Answer 25

Protraction, contralateral excursion

Question 26

What muscles elevate the mandible?

Answer 26

(closing)

Masseter, medial pterygoid, temporalis

Question 27

What muscles depress the madible?

Answer 27

(opening)

lateral pterygoids, supra- and infrahyoid muscle

Question 28

What muscles protrude the mandible?

Answer 28

Masseter (superficial), lateral pterygoid

Question 29

What muscles retract the mandible?

Answer 29

Temporalis (posterior, horizontal fibers), masseter (deep)

Question 30

What muscles facilitate lateral excursion of the mandible to the right?

Answer 30

Right masseter, right temporalis, left lateral pterygoid, left medial pterygoid

Question 31

What muscles facilitate lateral excursion of the mandible to the left?

Answer 31

Left masseter, left temporalis, right lateral pterygoid, right medial pterygoid