Chapter 8

Classifying JointsFunctions

Flexibility for movement Hold bones together

Structural Classification (binding tissue and cavity)Fibrous CartilaginousSynovial

Functional Classification (amount of movement)Synarthroses – immovable; axial skeletonAmphiarthroses - slightly movable; axial skeletonDiathroses - freely moveable; limbs

Organizing JointsFibrous Joints Cartilaginous

JointsSynovial Joints

Binding material

Joined by fibrous tissue

Joined by articular (hyaline) cartilage

Separated by synovial fluid cavity

Cavity Present No No Yes

Functional Type

Synarthroses Amphiarthroses Diarthroses

Examples SuturesSyndesmosesGomphoses

SynchondrosesSymphyses

Joints of limbs

Fibrous JointsSutures

Only b/w skull bonesBind, but allow growthComplete as an adult

(synostoses)Syndemoses

Longer than suturesLength determines mov’t*Interosseous membrane and

tibia-fibula distal endsGomphoses

Tooth in alveolar socketPeriodontal ligament

Cartilaginous Joints

SynchondrosesTemporary, become

synostosesEpiphyseal plates and

coastal cartilageSymphyses

Cartilage fused to fibrocartilage pad/plate

Strength with flexibilityIntervetevbral discs and

pubic symphysis

Synovial JointsArticular cartilageJoint (synovial) cavityArticular capsule

Fibrous capsule (ext-) DICTSynovial membrane (int-) LCT

Synovial fluidViscous, but thins with mov’t

Reinforcing ligamentsDouble jointed = looser/stretchier ligmanents and

capsuleRich blood and nerve innervationFatty pads for cushioning (hip and knee)Menisci divide cavity and improve fit (knee and jaw)

Synovial JointsPreventing friction

Bursae are flattend fibrous synovial sacs

Tendon sheaths are elongated bursa wrapped around a tendon

StabilityArticular surface shape

Determine mov’t & some stabilityLigaments

Prevent excessive/undesirable mov’t

Inadequate than stay stretched (taffy) = snapping

Muscle tone Tendons stay taut so reactive

Joint Articular ShapesPlane - articular surface is flat, nonaxial

Intercarpal and –tarsals; slip 1 or 2 waysHinge – cylindrical projection to a trough

Elbow and interphalengeal; 1 plane of mov’tPivot – rounded end into ring or “sleeve”

C1 & C2 or radius & ulna; 1 plane of mov’tCondyloid - oval surface into a depression

Metacarpophalangeal (knucles); 2 planes of mov’t

Saddle – concave and convex surfaceCarpometacarpal thumb joint; 2 planes of mov’t

Ball and socket – spherical end with a cup-like socketShoulder or hip joint; 3 planes mov’t

Synovial MovementsGliding

Slips surfaces across one another

Flexion/extension Reduces angle of joint/

increases angle

Abduction/adduction Away from center/ toward

midline

Pronation/supination Face or palm down/ face or

palm up

Rotation/circumductionTurning on an axis/ making

small circles

Inversion/eversionTurn sole medially/ turn sole

laterally

Dorsiflexion/plantar flextionFlex/ point

Protraction/retraction Jaw out/jaw in

Elevation/depressionLift superiorly/move

inferiorly

Knee JointSingle cavity w/ 3 jointsCapsule partially enclosesStrong vertical force, weak lateralPatellar ligament (knee-jerk)

Prevent hyperextensionFibular and tibial collateral ligaments

Prevent lateral and medial rotation w/ extensionAnterior and posterior cruciate ligaments (tibial

attach)Prevent forward sliding of tibia; back displacement of

tibia or forward femurPosteriorly, medially, up; anteriorly, laterally, up

Lateral and medial meniscus

anteriorcruciateligament

Temporomandibular Joint (TMJ)Mandibular condyle is egg-shapedTemporal bone is knob forward, concave fossaSide-to-side is lateral exclusion, unique to

mammalsShallow socket = easy dislocation

Reset: thumbs in molars, push inferior and posteriorPain from muscles tension

Clinical TermsSprain: stretching/tearing of a ligamentDislocation (luxation): bones forced out of positionBursitis: inflammation on bursa; blow or frictionArthritis: synovial membrane thickens, production

decreaseOsteoarthritis – degenerative; tissue thickens & bone spurs

formedRheumatoid arthritis - autoimmuneGouty arthritis – uric acid accumulation in soft tissue joints

Synovitis: inflammation of synovial membraneTendinitis: inflammation of tendon sheaths, overuse;