Exam 1 lecture: synovial jts and arthrokinematics Flashcards
biomechanical triad
skeleton, muscles, joints
parts of long bone
diaphysis metaphysis (x2) epiphysis (x2) physis (x2)
what is an apophysis?
accessory physis for tubercle, tuberosity, or epicondyle
what is the most common joint type in the extremities?
synovial jt
what is subchondral bone? what are its properties?
tip of epiphysis, deep to articular cartilage dense/cancellous/spongy bone; shock absorber
what is synovial fluid made of?
GAGs - glycosaminoglycans *hyaluronic acid is most important GAG*
functions of synovial fluid
shock absorption lubrication nutrient supply to cartilage waste removal from cartilage
what happens if you don’t move your joints in regards to synovial fluid/cartilage?
decreased function due to no movement of nutrients in and out of cartilage; aging process speeds up
2 layers of synovial membrane
intima: epithelioid layer subintima: CT layer
which layer of the synovial membrane is vascularized?
subintima
which layer of the synovial membrane is innervated?
subintima
what are the functions of the synovial membrane?
produce and resorb synovial fluid immunity for joint cavity
what are found in the transition zones of synovial membrane?
villi and fibrocartilage
what types of cell would you find in the synovial membrane?
macrophages secretory fibroblast lipocyte
what type of capillaries are in the synovial membrane? for what purpose?
fenestrated capillaries; increased fluid exchange
t or f: the synovial membrane does not contain lymphatic vessels.
false.
what type of CT is the fibrous joint capsule made up of?
dense irregular CT
what are the functions of the fibrous joint capsule?
support/stabilize: static support guide and limit movements absorb shock
t or f: the synovial joint capsule is inelastic and non-contractile.
true.
static vs. dynamic support
dynamic support: comes from muscles static support: anything that is not muscle support; sometimes also referred to as primary support even though it is the last form of support before injury.
Sharpey’s fibers
attachment sites of ligament to bone; blends together continuously (as opposed to a rigid line of transition)
Wolff’s law
tissues react to external forces; tissues will adapt to forces placed on them
t or f: the fibrous joint capsule is vascularized but not innervated.
false. the fibrous joint capsule is both vascularized and innervated.
bursa: definition and function
a “sac” of fluid meant to help lubricate and cushion areas where two bones rub together - really a potential space
t or f: some bursa communicate with joint capsules regularly, while others may communicate through defects in the capsule or not at all.
true.
what is the most common type or articular cartilage?
hyaline cartilage
what are the main components of articular cartilage?
low cell population density H2O (80% of total wt) collagen (60-70% of dry weight) GAGs (proteoglycans, 30-40% of dry weight)
what is the function of collagen?
hold cartilage together resist shear & expansive forces
what joints are lined by fibrocartilage?
AC jt SC jt TMJ 1/2 of SI jt
t or f: collagen fibers are more parallel on bony side of cartilage cap and more perpendicular near articular surface.
false. fibers are more parallel near articular surface due to shear forces at the surface.
what is important for GAGs to function?
GAGs must be sulfated for function
give 4 examples of GAGs
chondroitin sulfate* glucosamine sulfate* keratin sulfate hyaluronic acid *most important in cartilage matrix
cartilage matrix is hydrophobic or hydrophilic?
hydrophilic
why are small compressive loads better than large compressive loads on cartilage?
large compressive loads squeeze fluid film out of the cartilage.
why are rapid oscillations/no oscillations bad?
decreased fluid exchange starves cartilage (e.g. immobilization, sustained load, vibratory tools)
what changes occur in hydrostatic lubrication in DJD?
cell numbers decrease GAGs decrease decreased lubrication –> serous fluid increases increased calcification
what happens to the subchondral bone in DJD?
calcification –> increased rigidity increased thickness –> increased rigidity and impedes nutrient delivery/waste removal sclerosis on x-rays decreased shock absorption - more dense like cortical bone
what causes DJD?
injury, wear and tear, increased mechanical stress, muscle weakness, abnormal support, decreased cartilage, decreased synovial fluid, aging, etc.
4 joints that include a disc
AC (child –> early 20’s) SC TMJ ulnocarpal (TFC = triangular fibrocartilage)
2 joints that include a meniscus
knee AC (late 20’s –> early 30’s)
2 types of intra-articular cartilage
disc, meniscus
what type of cartilage is intra-articular cartilage?
fibrocartilage
what are the functions of intra-articular cartilage?
shock absorption congruency stability decreased friction increased motion
is intra-articular cartilage innervated/vascularized?
yes, but only the outer 1/3
what are some effects of aging on intra-articular cartilage?
decreased vascularization decreased chondrocyte population decreased GAGs and collagen decreased shock absorption and flexibility increased collagen fiber size
most extremity synovial joints are _______ and ________
diarthrodial, highly mobile
3 joint classifications
simple compound complex
simple joint
2 articular surfaces (1 articulation) simple joints usually have simple movements
compound joint
2 or more articulations
complex joint
1 or more articulations + intra-articular disc/meniscus
joint complex
several joints acting together as a functional group
what type of joint is the subtalar joint?
compound
what type of joint is the tibiofemoral joint?
compound
what type of joint is the patellofemoral joint?
compound
what are some examples of joint complexes?
knee, shoulder, elbow, wrist, etc.
what type of joints are the MP joints?
simple
what type of joint is the AC joint?
complex
name a joint that is both a complex joint and a joint complex
elbow, wrist, knee
name a joint that is a joint complex but not a complex joint.
ankle
what type of joint is the SC joint?
complex
what type of joint is the TMJ?
complex
what are the 6 anatomical/morphological joint classifications?
spheroid = enarthrosis = ball & socket ellipsoid = condyloid arthroid = planar = gliding sellar = saddle ginglymus = hinge trochoid = pivot
what are examples of a spheroid joint?
hip, shoulder
what is an example of an ellipsoid joint?
tibiofemoral jt
what is an example of an arthroid joint?
carpal jts
what is an example of a sellar joint?
thumb
what is an example of a ginglymus joint?
MP joints
what is an example of a trochoid joint?
head of radius to capitulum
what are the 4 joint motion classifications?
angular (flexion, extention, abduction, adduction) translational (primarily gliding) rotational circumduction (combination of all of the above)
what are the 4 joint classifications based on axes of motion?
uniaxial biaxial polyaxial nonaxial
what is an example of a uniaxial joint?
IP joints
what is an example of a biaxial joint?
MP joints
what is an example of a polyaxial joint?
shoulder, hip
what is an example of a nonaxial joint?
carpal joints
what is the shape of most joints? why?
irregular ovoid; non-linear/accessory motions b/t joint surfaces
what is the significance of crooked or crank shaped bones?
actions differ from joint motion
t or f: osteokinematics is based on mechanical axis, not axis of rotation
true
what are the two types of motion according to osteokinematics?
spin, swing
what movement would be assoc. w/rotation causing an angular type of movement?
rotation of the head of the femur (spin) –> flexion/extension of the femur
when would spin cause rotation?
when mechanical axis is parallel to long axis
t or f: in spin, the mechanical axis is stationary
true
t or f: spin usually –> rotation
false b/c bones are crooked/crank shaped
t or f: pure spin does not occur
true
what movement does spin usually accompany?
swing
why do we not use spin synonymously w/rotation?
spin can produce angular or rotational movement
what is impure swing?
spin + swing
what is the screw home mechanism?
knee must externally rotate during last 15˚ of extension
what is the screw home mechanism a good example of?
conjoint rotation
what is arthrokinematics?
joint classification based on movement at articular surfaces
what are the 3 types of movement assoc. w/arthrokinematics?
rolle slide/glide spin
what is conjoint rotation?
roll + slide + spin
what are the problems with pure roll?
progression distraction impingement
what are the problems with pure slide?
progression distraction impingement
what is the most common movement happening in an adjustment?
slide
which always moves in the direction of angular movement: roll or slide?
roll
what is the rule for a convex on a concave surface?
slide is opposite roll
what is the rule for a concave on a convex surface?
slide is in the same direction as roll
conjunct/conjoint rotation
accessory rotation due to spin and swing occuring together
closed/tight packed position
joint, muscles, etc. are tight - joint surfaces are drawn closer together (e.g. end range of motion)
open/loose packed position
little tension in capsule, room for movement
resting position
most loose packed position
neutral position
standard 0˚ when measuring ROM
end play
joint is most prone to injury at end of ROM
what are the 7 functions of muscle?
shock absorption dynamic joint stabilization dynamic joint alignment acceleration deceleration heat production venous circulation
name the 3 types of muscle contraction
isometric isotonic isokinetic
isometric contraction
no change in length of muscle, no movement
isotonic contraction
produces joint motion w/variable velocity concentric: muscle shortening eccentric: muscle lengthening, often more stress on muscle/tendon than concentric
isokinetic contraction
produces joint motion w/no constant velocity
what are extracapsular ligs?
ligaments that are not a part of the capsule, but support the capsule
what are the thickenings of the capsule?
capsular ligaments
