Temporal and Infratemporal Fossae and TMJ Region- Wilson

Question 1

Myofascial Pain disorder/ TMJ Disorder

Answer 1

• affects 20-20% of population
• complex syndrome with symptoms that include:
• pain around the ear TMJ and lateral part of face
• tenderness in the muscles of mastication
• open and closing of jaws you get popping sounds (crepidation)
• stiffness and or locking of joint

Question 2

What is the primary cause of the Myofascial Pain disorder/ TMJ Disorder? Why is it hard to diagnose or treat?

Answer 2

Primary cause: malocclusion

Treatment: align the teeth
need to have an orthodontist or get dentures so the pressures of chewing will be felt by the teeth and not TMJ

Psychiatry has a role in the diagnosis and treatment of TMJ

Question 3

Pyramid with TMJ at the top and occlusion and muscles of mastication at the bottom of the pyramid

Answer 3

occlusion is how your teeth meet if your teeth are straight or crooked; muscles of mastication

there is a dynamic relationship between all these three anatomical structures
IF you look at occlusion and TMJ, this was traditionally the cause of TMJ; as person’s teeth became crooked or was crooked at birth as the chews it would put an enormous amount of strain and stress on the TMJ, causing the TMJ to be injured or cause anomalies

if the TMJ is not working properly, this could put extra pressure on occlusion; the occlusion itself gets adjusted and teeth float to different position; bad TMJ can result in malocclusion; there’s a back and forth relationship here

Also there is a relationship btw the muscle of mastication (MM) and TMJ, MM work on a joint so if a joint has deformities or is not anatomically correct, then the muscles have to compensate and work differently and this could put strain and stress on MM allowing it become sore and tender; going in the other direction there are certain condition where a person will grind their teeth at night because of stress and this makes your MM very sore and wears out your TMJ

malocclusion and MM interact; so malocclusion will result in teeth having to compensate for occlusive surfaces not coming aligned and therefore they work at an angle they are not designed to

muscles of mastication can wear the surface of the teeth flat resulting in inefficient chewing causing occlusion surface to change

Question 4

Neurological/Psychiatric Disorders Are Often Express Through the Face & Muscles of Mastication

Pre and Postcentral gyrus

Answer 4

the oral cavity has a huge representation both sensory and motor in the pre and postcentral gyrus

this means that when people have psychiatric or neurological problems they will be expressed through the oral cavity and therefore
one of the treatment for TMJ syndrome is therapy (anti-anxiety drug anti-stress drugs or talking therapy to work through emotional problems the pt may be experiencing or actually talking)

once you resolve the psychiatric problem most often the organic problems resolve as well

Psychiatry has a major role in the diagnosis and treatment of TMJ

Question 5

Lateral side of head

Answer 5

superior temporal line connect with zygomatic fossa = temporal fossa

inferior temporal line where fascia attaches and where the temporalis muscle attaches

Infratemporal fossa is inferior to the temporal fossa; to gain access to it you have to cut off the zygomatic arch and ramus of the mandible

Question 6

What are the landmarks for infratemporal fossa?

Answer 6

• maxilla (anterior)
• styloid process (posterior)
• medial boundary: pterygoid process

-coming medial to the infratemporal fossa (IF) is the pterygomaxillary fissure which allows communication btw the infratemporal fossa and pterygopalatine fossa and the inferior orbital fissure

it is through pterygomaxillary fissure that arteries in particular branches of the maxillary artery
can gain access to structures in the middle of the face such as the nasal and oral cavity

Question 7

Different view of the Temporal fossa and infratemporal fossa

Answer 7

3 bony landmarks:

• ramus of the mandible
• lateral pterygoid plate
• zygomatic arch
• directly above zygomatic arch is the temporal fossa
• the area btw the lateral pterygoid plate and the ramus of the mandible is IF

Question 8

What are the major structures you find in the infratemporal and temporal fossa?

Answer 8

Contents of the infratemporal fossa:

• pterygoid muscles
• branches of the mandibular nerve: chorda tympani, otic ganglion
• maxillary artery
• pterygoid venous plexus

Contents of the temporal fossa:

• temporalis muscle
• auriculotemporal nerve
• superficial temporal artery

Question 9

Temporomandibular Joint

Answer 9

an articulation between the mandible and temporal bone

an unusual joint

head: mandibular condyle covered in cartilage

condyle head is connected to the body via the ramus neck

Question 10

Fovea

Answer 10

a spot the inferior head of the lateral pterygoid muscle inserts here

Question 11

What are the two different surfaces of the temporal bone where the condyle will articulate?

Answer 11

mandibular fossa and articular eminence

Landmarks to position yourselc :

• external auditory meatus
• mastoid process behind EAD
• zygomatic process

sandwiched btw EAD and zygomatic process are the articular surfaces of temporal part of the TMJ (upper half of TMJ)

the condyle of the TMJ will rotate back and forth btw the fossa and the eminence during opening and closing of mouth during protrusion and retraction of the mandible

when you look at the skull
these bony surfaces will be very smooth if it is a healthy TMJ; the pressure of chewing should be observed by the teeth; if you have proper occlusive surface there should be no pressure on the TMJ

Question 12

What are the other two bony landmarks related to TMJ that are important?

Answer 12

medial to the mandibular fossa is the spine of sphenoid bone: sphenomandibular ligament attaches here and helps to divide the maxillary artery into its first and second parts

petrotympanic fissure: the chorda tympani exits the middle ear cavity and runs through the infratemporal fossa to join the lingual nerve; will hitchhike with the lingual nerve to reach the tongue to provide taste to the anterior 2/3 of tongue and those autonomic fibers in the chorda tympani hitchhike with the lingual nerve to provide secretomotor innervation to salivary glands in the lower half of the oral cavity

this petrotympanic fissure is very important due to PS fibers providing visceral motor control over salivary glands

Question 13

TMJ is a synovial joint but what makes it different?

Answer 13

hip joint is a synovial joint (TYPICAL):
-articular capsule of collagen fibers
-articular surface of bone that rub against each other are covered with hyaline cartilage (resilient, covers joints that are weight supporting)
the presence of a synovial membrane , a very thin one cell layer membrane that secretes synovial fluid which forms a macroscopic layer covering the hyaline cartilages lubricating the surfaces of the hyaline cartilages making the movement very smooth and without pain or friction

• TMJ is very similar to the hip joint but has differences:
  1. the articular surfaces of the temporal bone and mandible are covered with FIBROCARTILAGE (fragile, TMJ is not a weight bearing joint)
  2. articular disk is found inside the capsule and is composed of fibrocartilage; is biconcave

Question 14

Anatomical changes in the TMJ Syndrome

Answer 14

• articular eminence is ground flat
• condyle is very flat
• the articular disc is flat instead of biconcave
• erosion and atrophy of fossa and condyle with loss of meniscus
• Normally, the forces of chewing are absorbed by the teeth

There is internal malarrangment because of malocclusion. When the pt tries to chew something pressure was being transmitted up into the TMJ causing deterioration of soft tissues.

malocclusion: missing teeth, teeth do not line up properly

Question 15

The TMJ ligament is a thickening of the lateral wall of the articular capsule

Answer 15

parts of the articular capsule which forms a band called the TMJ ligament (intrinsic) where all the fibers are running in one direction and it prevents the TMJ from going too posteriorly or inferiorly

however does not support of the TMJ anteriorly

Question 16

Accessory ligament (extrinsic)

Answer 16

TMJ capsule

stylomandibular lig
-that goes from the spine of sphenoid and attaches to the lingula around the mandibular foramen

• the main artery in the area is the maxillary
• sphenomandibular ligament is a landmark for dividing this artery into a 2 parts; there is a 3rd part we can’t see, it ends when the maxillary artery enters through the pterygomaxillary fissure

-the stylomandibular ligament goes from the styloid process to the angle of the mandible

they are NOT important in terms of function

Question 17

Accessory ligament (extrinsic) in regards to maxillary artery

Answer 17

sphenomandibular ligament is a landmark for dividing this artery; landmark between the 1st and 2nd part of the maxillary artery

3rd part we cannot see as it enters the pterygomaxillary fissure

Question 18

Eagle’s syndrome produces similar symptoms as TMJ syndrome.

Answer 18

-stylohyoid ligament goes from the tip of the styloid process to the hyoid bone (Stylomandibular ligament is anterior to it)

-STYLOHYOID ligament can become calcified resulting in the elongation of the styloid process; when this elongation occurs it can result in EAGLE’S syndrome:
Presentation: looks like TMJ, limits how much person can open cavity
-the problem is the elongation of the styloid process because of calcified stylohyoid ligament

Question 19

What is the differential btw TMJ and eagles syndrome?

Answer 19

swallowing

• when you swallow your hyoid bone will be elevated
• when the stylohyoid ligament is calcified, swallowing will be painful

TMJ syndrome will not produce pain while swallowing; Eagle’s syndrome will

Question 20

An articular disk is found inside the capsule.

The articular disc is bi-concaved (like an RBC).

Answer 20

biconcave shape is important in terms of TMJ syndrome

• The superior head of lateral pterygoid inserts into the capsule and disc.
• the disc is very closely attached particularly to the condyle so as the condyle goes back and forth btw the fossa and eminence the disc will move with the condyle

-attached to the condyle and disc is the superior head of the lateral pterygoid; when this muscle contracts it pulls the disc anteriorly as well as the capsule, its partner the inferior lateral pterygoid pulls with it the condyle anteriorly

Question 21

Subluxation (partial dislocation) and dislocation

Answer 21

Subluxation: normally disc is directly above the condyle but sometimes when you get stretching and deterioration of the attachment of disc to the capsule, the disc instead of being over the capsule will be slightly dislocated ,maybe in a more anterior or posterior position

Total dislocation: total stretching of the attachment of the disc to the capsule can result in total dislocation; no articular relationship between the disc, condyle of the mandible or the temporal bone; it is outside of the normal movements

when you get a totally dislocated disc, during opening and closing of jaw the disc will get wedged in between the condyle and temporal bones locking the TMJ in position so the jaw gets locked open or closed and the person can’t move their jaw

dislocated disc can cause TMJ syndrome

Question 22

Subtle cause of TMJ that does not necessarily involve occlusion.

Answer 22

crepitation: popping sounds during opening or closing of jaw usually because there is a flattening of the ligaments attached to the disc allowing the disc to lag behind moving to the condyle which is part of TMJ syndrome

Question 23

What is protrusion and retraction of the mandible?

Answer 23

Protrusion:

• Anterior Sliding of the Mandible
• sliding of the condyle from the mandibular fossa to the articular eminence

Retraction:

• Posterior Sliding of the Mandible
• condyle goes from eminence to the mandibular fossa

Question 24

What vulnerability is there with protrusion?

Answer 24

• the TMJ is in a very unstable position
• high probably TMJ could dislocate anteriorly
• when you open your jaw
• caused by yawning

Question 25

What do you do when you have a anterior TMJ dislocation?

Answer 25

put gentle pressure on TMJ and push it DOWN, the soft tissue will allow the condyle to go BACK to the mandibular fossa

To reduce a dislocated TMJ,
the mandible is gently pressed:
1. down
2. back

Question 26

Lateral excursion

Answer 26

condyle on one side is protruded and the other side is retracted resulting in lateral deviation or excursion of the TMJ to the right or left

deviation of jaw to the right:

• left tmj is protruded
• right tmj is retracted

deviation of jaw to left:

• left tmj is retracted
• right tmj is protruded

Question 27

What happens to the condyle during opening and closing of jaw?

Answer 27

Opening: condyle goes from fossa to eminence; as the condyle rotates down it opens the mouth; the more you rotate the mandible inferiorly, the condyle is going anteriorly; opening of mouth is when TMJ is most vulnerable

close: condyle goes from eminence back to mandibular fossa; where TMJ is most stable

Question 28

Muscles of mastication involved in chewing

Answer 28

1. temporalis
2. masseter
3. lateral pterygoid
4. medial pterygoid

• all these muscles are innervated by mandibular division of the trigeminal nerve
• derived from the first branchial arch

Question 29

Temporalis

Answer 29

temporalis: is the positioner of the jaw allowing the alignment of the teeth to ensure efficient chewing; has broad origin (temporal fossa) with 3 heads: anterior to elevate the jaw, posterior head to pull the coronoid process posteriorly= retracting the jaw, intermediate to elevate the jaw and assist in retracting the jaw narrow insertion (coronoid process)

Question 30

Masseter

Answer 30

masseter: a two headed muscles; you see superficial head on cadaver; when it contracts moves the angle of mandible to the zygomatic arch; assists in protrusion; deep to the superficial head are the deep head which elevate the jaw and move the condyle posteriorly during contraction (retraction of jaw)

Question 31

Medial pterygoid

Answer 31

• it is a mirror image of the masseter: the difference is that the masseter is on the outside of the ramus of the mandible, the medial pterygoid is on the inside
• origin: arises from the inside surface of lateral pterygoid plate
• insertion: inserting into the angle of the mandible (same insertion as masseter but on the inside)

-primary function is the elevation of the jaw

Coronal section through the mandible can show the relationship between medial pterygoid and masseter

they both form a sling around the angle of the mandible so that when you protrude or retract the jaw those muscles assist in keeping that jaw moving in a single horizontal line; they are working synergistically with the prime mover for protrusion and retraction of the jaw

Question 32

Lateral pterygoid

Answer 32

• prime mover for PROTRUSION of the jaw
• forms the lateral surface

superior head (upper): attaches directly to capsule and disc of TMJ; can pull the disc and capsule anteriorly to keep the proper articular relationships btw the discs and the condyle; helps to control movements of the disc itself

inferior head (lower): attaches to the neck of mandible at the fovea

these heads are usually separated by the long buccal nerve landmark

Question 33

BRUXISM

Answer 33

is Clenching and Grinding of Teeth During Sleep:

• affects approximately 15% of the population
• women more prone
• stress, tension, anxiety and anger are often the cause
• wears down occlusal surfaces
• may be the source of myofascial pain in the TMJ syndrome

molar surface can be flat after a period of time; no occlusive surfaces

Question 34

Deep Cervical Fascia

Answer 34

fascia lata of the neck
surrounds the trapezius and the SCM

as it reaches the angle of mandible it splits and surrounds the muscles of mastication

defines a potential space= masticator space because it contains the muscles of mastication

important because you can get infections; can fill with hemorrhage or abscess material

Question 35

Masticator space and trismus (lockjaw)

Answer 35

At the mandible, the deep cervical fascia splits into superficial and deep laminae that surround the muscles of mastication and form the masticator space.

infections in the masticator space result in trismus (lockjaw) or spasms of the muscles of mastication.
This makes opening the jaw and draining the infection DIFFICULT!! With the jaw closed, the only access to the oral cavity is through the retromolar space

• trismus is spasms of the muscles of mastication
• caused by infections in the masticator space, fracture of mandible= muscles naturally go into contraction AKA protective splinting, blood infections
• specific to muscles of mastication

Question 36

Trismus: spasms of muscles of mastication usually due to trauma, infections and/or irritation.

Answer 36

abscess can track (move) posteriorly and enter the masticator space filling up with infection, muscle go into contraction causing locked jaw

An infection (e.g., dentoalveolar abscess) can tract into the masticator space, irritate the muscles and produce trismus (lock jaw)

Question 37

TETANUS GRIN

Answer 37

-produces a neurotoxin to make muscles of mastication and facial expression to go into spasms

Trismus, spasm of muscles mastication (and facial expression), because of tetanospasmin toxin (Clostridium tetani).

As more muscles are affected, eventually the diaphragm goes into spasm.

Question 38

Temporal Fascia

Answer 38

• attaches to the superior temporal line
• Infections can develop deep to the superficial temporal fascia and fill-up the temporal space
• Temporal Abscess Following Tooth Abstraction

Question 39

Mandibular nerve

Answer 39

lateral view you see
the branches of the mandibular nerve:

• long buccal nerve: most anterior branch and it goes towards the buccinator
• lingual nerve: goes to the tongue; if you follow it right below it is the submandibular ganglion: postganglionic PS fibers that innervate sublingual, submandibular glands
• inferior alveolar nerve: has a mylohyoid branch going to the anterior belly digastric and mylohyoid muscle
• auriculotemporal nerve: most posterior branch

Question 40

long buccal nerve

Answer 40

provides motor innervation to these muscles (two heads of the lateral pterygoid muscle) but as it leaves these muscles it is purely a sensory nerve; provides sensory innervation of skin outside of the buccinator and mucosa of the buccinator
-does not provide motor innervated the buccinator!! (derived from second pharyngeal arch and innervated by the buccal branch of the facial nerve)
runs between the two heads of the lateral pterygoid muscle

Question 41

inferior alveolar nerve

Answer 41

gives off a small nerve called the mylohyoid nerve that innervates the mylohyoid muscle and the anterior belly of digastric; then the nerve enters the ramus of the mandible through the mandibular foramen; then it runs in the body of the foramen giving off sensory innervation to all of the mandibular teeth including the molars, etc.

• innervates all of the teeth
• leaves the mandible through the mental foramen where it becomes cutaneous right in front of the jaw supplying the chin and lower lip
• provide sensory innervation to the front of the mandible

Question 42

lingual nerve

Answer 42

• closely related to the inferior alveolar nerve
• goes to the tongue
• changes in its course in the infratemporal fossa; when it comes off the main division of V3 it is carrying only GSA sensory fibers (pain, temp, touch) to the anterior 2/3 of tongue
• if the lingual nerve is cut before merging with the chorda tympani, you have anesthesia of the tongue but you still can taste

in the IF you get the nerve from facial called the chorda tympani which goes through the petrotympanic fissure right behind the mandibular fossa

Question 43

If there is a lesion before the merging of the PS fibers from CN VII to lingual nerve or after would you get the same symptoms?

Answer 43

• no because after merging, the lingual nerve is carrying GSA and now GSE and SVA (taste fibers to the anterior 2/3 of tongue) thus you would get
• anesthesia to tongue
• loss of taste to anterior 2/3 of tongue
• decreased amount of saliva production

follow this nerve down is the submandibular ganglion which is where the postganglionic fibers go and innervate the sublingual and submandibular glands

-if the lingual nerve is cut before merging with the chorda tympani as it is only carrying GSA fibers to the anterior 2/3 of the tongue, you would have anesthesia of the tongue but you can still taste

Question 44

Parasympathetic fibers from CN IX hitchhike with the auriculotemporal nerve to innervate the parotid gland.

Answer 44

Otic ganglion related to CN IX:

• found immediately medial to the mandibular nerve as it goes through the foramen ovale
• fibers from the lesser petrosal nerve come into the otic ganglion and synapses there; the postganglionic fibers from this ganglion join the auriculotemporal nerve to the parotid gland to provide secretomotor innervation to the parotid gland

So CN IX provides visceral innervation to the parotid by PS fibers from CN IX hitchhiking with the auriculotemporal nerve.

Question 45

One important relationship: the auriculotemporal nerve arises as two different roots from V3 that surround the middle meningeal artery (nerves surrounding an artery)

Answer 45

if the middle meningeal artery becomes inflamed, or if you’ve got phlebitis or an aneurysm forming this could put pressure on the two roots as they go around the middle meningeal artery, so just like the lingual nerve the auriculotemporal nerve has GSA fibers going to the temporal region and secretomotor fibers going to the parotid gland

LOOK FOR NERVES SURROUNDING ARTERIES!!!, that would be middle meningeal artery

Question 46

External carotid artery has what two terminal branches?

Answer 46

maxillary and superficial temporal artery

Question 47

Superficial temporal artery is important because?

Answer 47

• can palpate to take pulse
• old persons can form Temporal Giant Cell Arteritis: if afflicted can produce temporal headaches, fever, jaw claudication, reduced vision, diplopia, polymyalgia in muscles around the shoulders and gluteal region; signs include tender prominent temporal arteries with asymmetrical pulses, bruits, murmur of AR (regurgitation into the aorta)
• INFLAMMATION which have elevated C-reactive protein and erythrocyte sedimentation rate

Question 48

Maxillary artery is divided into what 3 parts by lateral pterygoid?

Answer 48

1. proximal to lateral pterygoid muscle:
   - MIDDLE MENINGEAL ARTERY
   - INFERIOR ALVEOLAR ARTERY
   - deep auricular
   - anterior tympanic

the lingual nerve and the inferior alveolar nerve are close together, easily confused in lab practicals; the long buccal branch is farther away

2. lateral or deep to lateral pterygoid muscle:
   - branches to muscles of mastication
3. enters pterygopalatine fossa and is distributed with branches of V2:
   - posterior superior alveolar
   - infraorbital
   - descending palatine
   - pharyngeal
   - artery of the pterygoid canal
   - sphenopalatine

know middle meningeal artery and inferior alveolar artery!!!!
-middle meningeal artery comes off the 1st part of the maxillary artery and is surrounded by the origin of the auriculotemporal nerve

sphenomandibular ligament is a landmark for dividing the maxillary artery into the 1st and 2nd parts

Question 49

Pterygoid venous plexus and ophthalmic veins communicate with the cavernous sinus in the cranium. Explain.

Answer 49

Pterygoid plexus:

• is found in the infratemporal fossa
• drains structures supplied by the maxillary artery
• communicates with the cavernous sinus
• are valveless so blood can go a variety of direction
• connected with veins in the face (orbital face)
• if you have an infection of the nose infection, it can go from the angular vein to the pterygoid plexus
• tooth infection can go into pterygoid plexus and thus into cavernous sinus