Neuro Exam 1 TMJ and Joints Flashcards
Synathrosis
An immovable joint like a suture, or gomphosis (b/w roots of teeth and alveolar process)
Amphiarthrosis
slightly movable joint, includes fibrocartillage between veterbrae (allows movement) and pubic symphysis (allows baby passage)
Diarthrosis
synovial-freely movable; lined by a synovial membrane which produces synovial fluid, includes typical and w/ articular disc
typical diarthrotic joint
the ends of two bones are covered by articular cartilage, ligaments join the bones together, capsular ligaments, and joint cavity (lined by synovial membrane)
Diarthrotic joint w/ articular disc
a synovial joint where everything is the same except there is an articulating disc seperating the two
Arthroidal joint
plane or gliding (acromioclavicular-clavicle and scapula)
Ginglymus joint
Hing; motion in one plane (elbow)
Trochoid joint
Pivot; rotation around one axis (i.e. dens and atlas joint-allows turning of head)
Condyloid joint
motion in two planes, no rotation (i.e. condyles of head on spine allows rocking side to side and front to back)
enarthroidal (ball and socket)
motion in all planes, plus rotation (i.e. hip joint)
Sellar (saddle or ellipsoid)
motion in two planes, some axial rotation (i.e. joint in thumb between first carpal and metacarpal)
TMJ Bones and covering
mandibular fossa of temporal bone, and head of mandibular condyle; articular surfaces covered by fibrous tissue
Classification of TMJ joint
Ginglymoarthroidal (hinge and gliding combination), bilateral (b/c on both sides of the jaw), and a synovial joint with an articular disc
Articular eminence
next to/bottom of mandibular fossa; roof or fossa is thin and may not bear pressure
Capsule (capsular ligament)
dense fibrous CT running from zygomatic arch to mandible; makes sure head stays in place
Makes sure the head of the condylar process remains in the mandibular fossa
capsule/capsular ligament
Articular Disc (meniscus)
made of dense fibrous tissue which divides the interior joint into sup. (gliding) and inf. compartments (hinge motion); peripheri is thicker and attaches to capsule
motion of the inf compartment of articular disc
hinge motion
motion of sup. compartment of articular disc
gliding motion
Composition of central region of articular disc
more fibrocartilage; more rigid
retrodiscal ligament composition (of articular disc)
more elastic fibers; more flexible
Temporomandibular (lateral) ligament
covers the capsular ligament; runs from zygomatic process of temporal bone to neck of mandibular condyle; prevents posterior displacement and excess lateral displacement of condyle
Sphenomandibular joint
runs from the spine of the sphenoid to the lingula of the mandible; becomes taught during excessive opening
becomes taut during excessive opening
sphenomandibular
prevents post. displacement and excess lateral displacement of condyle
temporomandibular ligament (lateral)
Stylomandibular ligament
runs from styloid process of temporal to the angle of the mandible; becomes taut in excessive protrusion
taut in protrusion
stylomandibular ligament
Nerve innervation of the TMJ
mandibular branch of the trigeminal (V3 of CN5); auriculotemporal (most branches), masseteric (branches to small ant. portion), deep temporal (branches to small ant. portion)
gives of branches to most of the joint
auriculotemporal
innervates the small ant. portion of the TMJ
the masseteric and deep temporal parts of the mandibular branch (V3) of the trigeminal (CN5)
Proprioceptive
sense of space (jaw open to long)
Pain Receptors
free nerve endings (overextension)
Blood Supply to TMJ
Superficial temporal art (post capsule) which is terminal branch of ext. carotid art. and maxillary artery (deeper into mandibular space) which is a terminal branch of ext. carotid artery
Where blood supply of TMJ branches from
External carotid artery
supplies post. capsule of TMJ
superficial temporal artery
Supplies the deep portion into the mandibular space of TMJ with blood
Maxillary artery
Motion of TMJ
combination of hinge and gliding
Protrusion
condyles move forward; discs glide down articular eminence
Retrusion
condyles move back, discs glide up the eminence
Depression
condyles rotate anteriorly around a horizontal axis, articular disc glides down,the articular eminence; when opening wide both protrusion and depression happen
condyles rotate anteriorly around a horizontal axis, articular disc glides down,the articular eminence
depression
elevation
discs glide back up the articular eminence and the condyles rotate posteriorly around a horizontal axis
lateral deviation to right
aka excursions; to the right –> disc on left slides down eminence and the right condyle rotates slightly anteriorly
lateral deviation to left
disc on right side slides down eminence and the left condyle rotates slightly anteriorly
muscles for protrusion
lateral pterygoids
muscle for retrusion
post/horizontal fibers of temporalis, deep fibers of massetter
depression
suprahyoids, infrahyoids, and lateral pterygoids in wide opening (involves protrusion)
elevation
massetter, temporalis, medial pterygoid
lateral deviation
opposite lateral pterygoid
disorders of function (and how common)
fractures of the mandible:
-30% at neck, at neck of condyle -25% at angle
-22% at chin
Subluxation (partial dislocation) and dislocation
-head of mandibular condyle is ahead of the articular tubercle
