100 FACTS OF TEMPOROMANDIBULAR JOINT
78) Rotation take place in which compartment of the TMJ?
Lower compartments (condyle - articular disc) - hinge-type rotation
48) What test is considered to be the gold standard for providing an image of the soft tissue of the TMJ, especially the position of the articular disc?
MRI
65) What is the anterior region of the TMJ innervated by?
Masseteric and deep temporal from V3 Sensory from V3
72) Where is the fibrous capsule of the TMJ firm? Why?
Medially and laterally It stabilizes mandible during movement
49) What is the major advantage of the MRI technique?
No exposure of the patient to x-ray radiation
46) What does the layer of fibrocartilaginous tissue provide to the TMJ?
Offers resistance against both compressive and lateral forces
What is dislocation also referred as?
Open lock
76) Thicker layer of fibrous tissue which is reinforced by accessory ligaments?
Outer fibrous layer of the fibrous capsule of the TMJ
98) Anterior guidance/anterior coupling is determined by?
Overbite Overjet
74) Large amounts of synovial fluids in the TMJ an indication of?
Painful internal derangements
92) The maximum opening movement of mandible depending on the age and size?
50-60mm
73) Where is the fibrous capsule of the TMJ loose? Why?
Anterior and posterior. Allow mandibular movement
81) Muscles helps in closing the mouth/elevating the mandible results from bilateral contraction of which three muscles?
Anterior fibers (vertical fibers) of right and left temporalis muscle Right and left masseter muscle Right and left medial pterygoid muscle
Dislocation of the TMJ is almost always? It happens during?
Anteriorly. Laughing or yawning
54) A patient has clicking in their TMJ where is this joint most likely to be displaced?
Anteromedial
Where does the collateral ligaments of the run?
Arise from the periphery of the disc and are attached to the medial and lateral poles of the condyle.
67) What parts of the TMJ are not innervated?
Articular cartilage & central part of the articular disc
Composed of dense fibrous connective tissue, and it is positioned in between the condyle and the fossa, dividing the joint into superior and inferior spaces?
Articular disc
59) What is considered to be the functional part of the TMJ?
Articular eminence
58) What is considered to be the nonfunctioning portion of the TMJ?
Articular fossa (anterior 3/4 of large mandibular fossa)
What is the function of the superior belly of the lateral pterygoid muscle?
Assist in stabilizing the position of the articular disk during closing
64) What is the capsule of the TMJ innervated by?
Auriculotemporal nerve (V3)
85) Do central portion of articular disc is vascular?
Avascular & lack of innervation at central portion of articular disc
82) Retrusion of jaw results from the bilateral contraction of?
Bilateral contraction of posterior fibers (horizontal fibers) of the temporalis muscle.
93) Which movements are the limits to which mandible can move?
Border movements
68) Are myelinated or unmyelinated nerves seen in the TMJ?
Both
95) Which jaw position is ligament guided position?
Centric relation
50) What sound is made by the articular disc when displaced to the anterior of the condyle?
Clicking
What are collateral ligaments (discal ligaments) made from?
Collagenous connective tissue - it does not stretch
55) What occurs during disc displacement of the TMJ?
Collateral ligaments become elongated/torn. Allows lateral pterygoid to pull articular disc out of place
60) What is it that connects the mandible to the temporal bone?
Combined hinge and gliding joint
83) Anteroinferior aspect of mandibular condyle is ____?
Concave
44) What kind of tissue is attached to the anterior band of the articular disk?
Contiguous with the capsular ligament, the condyle, and the superior belly of lateral pterygoid muscle.
62) The vessel supplies the TMJ?
Deep temporal and masseteric of maxillary artery Branches of superficial temporal from external carotid
51) What is a crepitation sound or a crepitus in the TMJ usually associated with?
Degenerative process (osteoarthritis) of the condyle
45) What are the articular surfaces of the TMJ covered with?
Dense fibrous connective tissue
What is another name for collateral ligaments?
Discal Ligaments
96) In protrusive movements, the condyles of mandible have moved in which direction?
Downward & forward direction
79) With the fracture of condylar neck, why condylar head remains in the mandibular fossa?
Due to TMJ ligament (main stabilizing ligament of the TMJ). It restricts the downward and posterior movement of the mandible & guides the forward motion of the condyle during opening.
What is the function of the temporalis?
Elevation of mand. (Jaw closing) Retraction of the mand. (lower jaw backward)
What is the function of the masseter?
Elevation of the mandible (jaw closing)
What is the function of the medial pterygoid?
Elevation of the mandible (jaw closing)
47) What is the shape of the condyle?
Elliptically shaped long axis is oriented mediolaterally
Where does the inferior belly of the lateral pterygoid run?
From lateral pterygoid plate to neck of condyle
Where does the temporomandibular ligament run?
From the articular eminence to the mandibular condyle to the lateral surface of the zygomatic arch and to the tubercle on its lower border; below, to the lateral surface and posterior border of the neck of the mandible.
90) Pure rotation of mandible involves which two planes of movement?
Frontal plane - up and down Sagittal plane - forward & backward
94) Which movements generally occur within the border movements?
Functional movements
86) Nonfunctional part of TMJ? Articular fossa
Functional part of TMJ? Articular eminence/articular tubercle
56) What type of joint is the TMJ?
Ginglymoarthroidal joint
Where does the superior belly of the lateral pterygoid run?
Greater wing of the sphenoid & infratemporal crest Inserts on joint capsule, articular disk and condyle of neck
57) What type of movements does the TMJ allow?
Hinge like rotation & sliding
87) _______belly of lateral pterygoid inserts on the neck of the condyle?
Inferior belly
91) Most stable & most easily reproduced position.
Initiating position (centric relation)
70) What structure of the TMJ secretes the fluid that lubricates the TMJ?
Inner synovial layer of fibrous capsule
Where do you test a patient's temporomandibular joint tenderness and noise?
Joint palpated laterally over the posterior surface of the condyles with the mouth open
89) Fibrous capsule is fairly thin except laterally where it forms?
Lateral TMJ ligament Medially & laterally, the capsule is firm to stabilize the mandibular movements
What occurs with unilateral contraction of the lateral pterygoids?
Lateral deviation of mandible
What is another name for temporomandibular ligament?
Lateral ligament
99) Anterior guidance is the guidance provided by the anterior teeth when the mandible goes into a _____ movement?
Lateral or protrusive movement
Which muscle will cause a deviation of the mandible when protruding to the side of the damage?
Lateral pterygoid
71) The fibrous capsule of the TMJ is fairly thin except where?
Laterally where it forms the temporomandibular ligament (lateral)
42) Which band is the thicker of the two on the articular disk? Anterior or posterior?
Posterior
What occurs with bilateral contraction of the lateral pterygoid muscles?
Protrusion of the mandible
What are the functions of the temporomandibular ligament?
Provides lateral reinforcement Prevents posterior and inferior displacement of condyle Main stabilizing ligament
100. Muscle guided position? Tooth guided position?
Rest position of mandible or postural position. Centric occlusion / intercuspal position.
75) What is the purpose of the joint capsule and ligaments of the TMJ?
Restrict excessive displacement of the mandible
43) What kind of tissue is attached to the posterior articular disk?
Retrodiscal tissue
69) What is the source of proprioception in the TMJ?
Retrodiscal tissue
Which component of the TMJ has the most vasculature and innervation?
Retrodiscal tissue
97) Which movement require condyles to move backward and upward?
Retrusive movement
84) Posterior aspect of mandibular condyle is ____?
Rounded & convex
52) What is a dull thud in the TMJ usually associated with?
Self-reducing subluxation of the condyle
What is the function of the inferior heads of the lateral pterygoid?
Slight depression of the mandible (jaw closing)
What ligament is most damaged when using an inferior alveolar nerve block?
Sphenomandibular ligament
What are considered to be the accessory ligaments of the TMJ? What is their function?
Sphenomandibular ligament & stylomandibular ligament. Limit excessive openings.
What is the function of the collateral ligaments?
Stabilize the disc on top of the condyle Resist movements of disc away from condyle during function
Hypermobility or hypertranslation of the mandible?
Subluxation
63) What is the venous drainage of the TMJ?
Superficial temporal vein Maxillary vein Pterygoid plexus
What are the two parts of the lateral pterygoid?
Superior belly and inferior belly
61) What is the only movable joint in the skull that has dense fibrous connective tissue on its articular surfaces?
TMJ
40) What is the middle part of the articular disk called?
Thinner central intermediate zone
80) The mandible will always deviate to the side of injury. True or false?
True
Condyles are not symmetrical nor identical. True or false?
True
77) Translation take place in which compartment of the TMJ?
Upper compartment (mandibular fossa - articular disc)
88) Dislocation of either or both TMJ can occur?
When the condyle translates anterior to the crest of the articular eminence
What is the difference between dislocation and subluxation?
With subluxation patient can return the mandible to its normal position without assistance of the dentist
Where is the sphenomandibular ligament attached?
from the spina angularis of the sphenoid bone, to the lingula of the mandibular foramen.
Where does the stylomandibular ligament attach?
styloid process to angle of mandible
53) What is another term for ear ringing?
tinnitus