exam 3: TMJ Flashcards
TMJ innervation
ruffini corpuscles
proprioception
TMJ innervation
pacinian corpuscles
dynamic mechanoreception
TMJ innervation
golgi tendon organs
static mechanoreception
TMJ innervation
free nerve endings
pain
the TMJ is is classified as a
synovial sliding-ginglymoid (hinged) joint
synovial joints permit movement between
2 bones
each bone of a synovial joint is covered by
hyaline cartilage
in a synovial joint, the two bones are united and surrounded by a
fibrous capsule thereby creating a joint cavity
the synovial joint cavity is filled with:
1mL
that is derived from villus cells which line the internal surface of the capsule
synovial fluid
what separates the the bones in tmj synovial joint
fibrous disc
in tmj, both the condylar neck and head develop by
endochondral ossification
both the condylar neck and head develops by
endochondral ossification
the condylar head develops by endochondral ossification and has multidirectional growth capacity.
Unlike long bones of the body, which also develop by endochondral ossification, the cartilage cells in the head and neck do NOT exhibit__________(a characteristic of the epiphyseal growth plates in long bone)
ordered columns
bones of the TMJ are the ______ and the ____
glenoid fossa and
mandibular condyle
what attaches to the joint capsule and articular disc (aka meniscus)
superior head of lateral pterygoid
what attaches to the condylar in the pterygoid fovea
inferior head of lateral pterygoid
the articulating surfaces are covered with a layer of:
fibrous tissue
with increasing age, the deeper portions of the fibrous covering may exhibit
islands of cartilage
comprised of collagen and elastic fibrous connective tissue, fat cells, and is highly vascular.
elastic fibers from this insert into the petrotympanic fissure
retrodiscal connective tissue (aka bilaminar zone)
the disc is attached to what surfaces of the condyle but not attached to:
thus, when the mandible moves the disc moves as well, traveling all over the anterior surface of the articular fossa
attached to medial and lateral surfaces of condyle but not temporal bone
all articulation is on what portion of the disc
fibrous
this dense area also restricts the posterior movement of the mandible and maintains the condyle in the anterior part of the glenoid fossa
disc
what area allows the mandible to move freely in an anterior direction
vascular retrodiscal area
what lines the inner surface of the fibrous capsule
synovial membrane
the tmj synovial membrane consists of three distinct layers of tissue.
1. most peripheral (external) layer is the
2. intermediate layer is the
3. most internal layer is
- fibrous capsule of the joint
- vascular subintima
- intimal layer
intimal layer contains 2 cell types:
type A synovial cells
type B synovial cells
macrophage-like cells that exhibit phagocytic functions and are capable of producing inflammatory cytokines
type A synovial cells( of intimal layer)
fibroblast-like cells that synthesize hyaluronate which is a major component of the synovial fluid in both the superior and inferior compartment of the joint
type B synovial cells
chronic or acute joint trauma may cause the type A synovial cells to undergo a ______transformation into multinucleated giant cells that exhibit osetoclastic-like functions (resorption of bone and cartilage)
thus, the articular surfaces, including the joint meniscus, are subjected to cellular mediated surface resorption as long as levels of IL-1, IL-6, IL-8 and TNF are elevated
syncytial (fusing)
if the inflammatory response is of sufficient intensity and duration, bone and cartilage resorption can also take place within the ____________ of the condylar head and subjacent condylar neck. this resorption can actually occur simultaneously on both the external and internal surfaces of the condyle
spongiosa of condylar head and neck
arachidonic acid pathway
- injury to cell membrane
- membrane phospholipid
- phospholipase
- arachidonic acid
splits into lipoxygenase and cycloxygenase
(arachidonic acid pathway)
lipoxygenase:
cycloxygenase:
lipoxygenase:
to leukotrienes
to chemotaxis vascular permeability
cycloxygenase:
splits into both prostaglandins
(vasodilation/edema/pain) and
thromboxanes (vasoconstriction)
(inflammatory joint disease)
1. chronic or acute joint trauma
- activation of arachidonic acid pathway
- leukotrienes, thromboxanes, prostaglandins
- type A synovial cells
- IL-1, IL-6, IL-8, TNF-a
- macrophage/osteoclastic activation
- tissue destruction
with these chronic inflammatory changes, _______are noted on the condylar heads. also a decreased vascularity is found in the retrodiscal area, leading to pain on function
osteophytes
the disc is trapped in the antero-medial position, causing limited opening, pain, and clicking upon opening
internal derangement
loss of articular coverings and synovial membranes, leading to direct bone-to-bone fusion
ankylosis resulting from untreated fracture
