Temporal and Infratemporal Fossae and TMJ Region- Wilson Flashcards
Myofascial Pain disorder/ TMJ Disorder
-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
What is the primary cause of the Myofascial Pain disorder/ TMJ Disorder? Why is it hard to diagnose or treat?
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
Pyramid with TMJ at the top and occlusion and muscles of mastication at the bottom of the pyramid
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
Neurological/Psychiatric Disorders Are Often Express Through the Face & Muscles of Mastication Pre and Postcentral gyrus
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
Lateral side of head
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
What are the landmarks for infratemporal fossa?
-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
Different view of the Temporal fossa and infratemporal fossa
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
What are the major structures you find in the infratemporal and temporal fossa?
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
Temporomandibular Joint
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
Fovea
a spot the inferior head of the lateral pterygoid muscle inserts here
What are the two different surfaces of the temporal bone where the condyle will articulate?
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
What are the other two bony landmarks related to TMJ that are important?
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
TMJ is a synovial joint but what makes it different?
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
Anatomical changes in the TMJ Syndrome
-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
The TMJ ligament is a thickening of the lateral wall of the articular capsule
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
Accessory ligament (extrinsic)
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
Accessory ligament (extrinsic) in regards to maxillary artery
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
Eagle’s syndrome produces similar symptoms as TMJ syndrome.
-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
What is the differential btw TMJ and eagles syndrome?
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
An articular disk is found inside the capsule. The articular disc is bi-concaved (like an RBC).
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
Subluxation (partial dislocation) and dislocation
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 move their jaw dislocated disc can cause TMJ syndrome
Subtle cause of TMJ that does not necessarily involve occlusion.
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
What is protrusion and retraction of the mandible?
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
What vulnerability is there with protrusion?
-the TMJ is a very unstable position -high probably TMJ could dislocate anteriorly -when you open your jaw -caused by yawning
What do you do when you have a anterior TMJ dislocation?
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
Lateral excursion
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
What happens to the condyle during opening and closing of jaw?
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
Muscles of mastication involved in chewing
- 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
Temporalis
temporalis: is the positioner of the jaw allowing the alignment of the teeth to ensure efficient chewing; has broad origin (temporal fossa) with 3 head: 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)
Masseter
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
Medial pterygoid
-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
Lateral pterygoid
-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
BRUXISM
is Clenching & 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
Deep Cervical Fascia
fascia lata of the neck surrounds the trapezius and the SCM as it reaches the angle of mandible it splits and surrounds the muslces of mastication defines a potential space= masticator space because it contains the muscles of mastication improtant becasue you can get infections; can fill with hemorrhage or abscess material
Masticator space and trismus (lockjaw)
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! -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
Trismus: spasms of muscles of mastication usually due to trauma, infections and/or irritation.
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)
Temporal part of TMJ
- Mandibular fossa
- Articular eminence
