H&N 9.2 Temporomandibular joint and infratemporal fossa.

Question 1

What type of joint is the TMJ?

Answer 1

Synovial hinge joint

movement mainly only in one direction, small amount laterally

Question 2

What are the articulations of the TMJ?

Answer 2

Chondyle of the mandible
articular tubercle of the temporal bone
mandibular fossa

Question 3

What is the articular disk of the TMJ?

Answer 3

a fibrous connective tissue which divides the TMJ into superior and inferior compartments

Question 4

What ligaments support the TMJ?

Which is the most important?

Answer 4

-Lateral ligament (most important)

• stylomandibular ligament
• sphenomandibular ligament

Question 5

Which muscles are involved in movment of the TMJ?

Answer 5

• temporalis
• lateral and medial pterygoids
• masseter
• hyoid muscles

Question 6

What muscles help to elevate the mandible?

Answer 6

-the temporalis, the masseter, the medial pterygoid

Question 7

What muscles help to depress the mandible?

Answer 7

-mainly done by gravity

infra/suprahyoid muscles help

Question 8

What muscle help to protrude the mandible?

Answer 8

-lateral pterygoid

Question 9

What muscle helps to retract the mandible?

Answer 9

Temporal muscle

Question 10

What muscles do lateral movements at the mandible?

Answer 10

temporal muscle of the same side,

pterygoids of the opposite side

Question 11

What is the innervation of the muscles involved in movement of the TMJ?

Answer 11

The mandibular branch of the trigeminal nerve

Muscles of mastication.

Question 12

What is locked jaw?

Answer 12

a TMJ dislocation when the head of the mandbile sits anteriorly to the articular tubercle of the temporal bone.

Question 13

What is the general cause of locked jaw?

Answer 13

A blow to the side of the jaw when it is open

Question 14

What must you consider in someone with locked jaw?

Answer 14

Dislocation of the other side of the mandible or a fracture.

Question 15

Apart from locked jaw, what conditions can affect the TMJ?

Answer 15

• Bruxism (teeth grinding)
• osteoarthritis
• interarticular disk derrangement

Question 16

What is the infratemporal fossa?

Answer 16

-irregularly shaped space beneath the zygomatic arch and deep to the ramus of the mandible.

Question 17

What are the borders of the infratemporal fossa?

Answer 17

• anterior- posterior maxilla
• posterior- temporal bone
• lateral- medial ramus
• medial- lateral pterygoid plate of sphenoid
• superior- greater wing of sphenoid
• inferior- medial pterygoid muscle

Question 18

What are the contents of the infratemporal fossa?

Answer 18

• medial and lateral pterygoids
• temporal muscle
• maxillary artery
• pterygoid venous plexus
• mandibular nerve
• inferior alveolar nerve
• lingual nerve
• otic ganglion
• buccal nerve
• chorda tympani

Question 19

Which nerves can be found within the infratemporal fossa?

Answer 19

• mandibular nerve
• inferior alveolar nerve
• buccal nerve
• lingual nerve
• chorda tympani
• otic ganglion

Question 20

What are the branches of the mandibular nerve?

Answer 20

• inferior alveolar nerve (sensory to lower teeth)
• lingual nerve (sensory to anterior 2/3 tongue. and carries chorda tympani with it)
• buccal nerve (sensory to cheek)

Question 21

What are some clinically relevant issues regarding the infratemporal fossa?

Answer 21

• site for isolated infections (rare, but can occur in diabetic patients, immuncompromised)
• infection can lead to cavernous sinus thrombosis (due to cavernous sinus connection with the pterygoid venous plexus)
• used as site for mandibular nerve block