Connective Tissue Biomechanics: Part II Flashcards Preview

DPT 726: Orthopaedic Foundations > Connective Tissue Biomechanics: Part II > Flashcards

Flashcards in Connective Tissue Biomechanics: Part II Deck (49)
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-connective tissue is the building block of bone, ligament, tendon, cartilage, joint capsules, intervertebral discs
-tissues affected by lifespan, injury, pathology, physical activity, hydration, sex
-understanding biologic and mechanical nature of these tissues provides insights necessary for prevention and management of injuries to these structures-allows us to better balance stress and recovery in these tissues


CT and Musculoskeletal System

-a junction between two or more bones
-allow for varying degrees of motion: rotation, transfer and absorb force
-allow for varying degrees of segmental growth


Osteoarthritis and Joints

-cartilage becomes worn away, spurs grow out from edge of bone, and synovial fluid increases
-stiff and sore joints
-do right type of exercise to get the most amount of mileage out of joint



-held together by dense irregular connective tissue
-allows little or no motion
-functions: bind bones together, transmit force with little joint motion
-stability and force transmission decrease potential for injury
-types: sutures, gomphoses, and syndesmoses



-2 bones grow together separated by only thin layers of fibrous periosteum



-binds teeth to bony sockets separated by only thin layers of fibrous periosteum



-joint bound by ligament only
-most mobility of fibrous joints



-cartilaginous joints
-bones separated by hyaline or fibrocartilage
-functions: joint stability, minimal to moderate movement, shock absorption
-types: symphysis and synchrosis


Symphysis Joint

-segment of fibrocartilage joints bones



-hyaline cartilage joins bones



-aka synovial joint
-has fluid filled cavity which encapsulates the ends of the bones
-possess a joint space
-affords a large amount of motion: bone ends are not directly connected


Characteristics of Synovial Joints

-synovial fluid provides lubrication and nutrition to cartilage and other structures within joint
-hyaline cartilage covers ends of bones
-articular capsule
-vascular supply system supplies capsule but does not enter joint cavity
-receptors provide proprioception
-other elements include menisci, fat pads, labrum


Hinge Joint

-movement about single axis
-one degree of freedom
-ex: humeroulnar joint
-degrees of freedom mean how many motions are available at the joint


Pivot Joint

-one segment is ring shaped
-other is shaped so it can rotate within ring
-ex: humeroulnar joint


Ellipsoid Joint

-one segment has an elongated convex surface
-the other is an elongated concave surface
-ex: radiocarpal joint, ulnocarpal joint


Ball and Socket

-one segment has a spherical convex end
-other has concave surface
-ex: hip joint


Plane Joint

-bones are relatively flat allowing for gliding and some rotation
-ex: carpal joints, subtalar joint


Saddle Joint

-aka sellar joints
-each segment has both convex and concave portions
-ex: sternoclavicular joint


Condyloid Joint

-shallower version of ball and socket joint
-ex: atlanto-occipital joint


Synovial Joint Capsule

-functions to encapsulate joint
-produces and contains synovial fluid
-provides nutrition for articular cartilage
-layers of capsule: fibrous/stratum fibrosum, synovial membrane/stratum synovium which has 3 layers subsynovial tissue and intima,
-stratum synovium is not a true membrane and is poorly vascularized
-type A synoviocytes clear joint of waste materials
-type B synoviocytes provide viscosity to synovial fluid
-synovial membrane lines entire joint cavity except over surfaces of articular cartilage menisci-absorb as well as secrete
-outer fibrous capsule thickens in some areas to form ligaments
-synovia-covered fat pads prevent creation of joint vacuum


Synovial Joint Fluid

-viscous, pale, yellow, clear fluid
-component of plasma to which glycoproteins and hyaluronic acid have been added
-also present in synovial sheaths and bursae
-has no fibrinogen so does not clot
-functions: absorbs and transmits forces, nourishes articular cartilage, decreases friction between joint surfaces, provides a medium for diffusion of nutrients and waste between articular cartilage and synovial membrane
-principle components: water, proteoglycans, hyaluronic acid, lubricin


Embryonic Development of Synovial Joints

-articular disk of mesenchymal tissue appears at the future site of joint
-dense tissue surrounds the primitive joint plate and is forerunner of the joint capsule
-clefts or spaces are evident by 7th or 8th week of embryonic life filled with tissue fluid
-active intrauterine movement is crucial for joint health


Joints and Exercise

-short-term effects of clinical exercise: articular cartilage thickens (improved force dissipation), 2-3 times increase in volume of synovial fluid in a joint
-evidence supports endurance exercise's benefits over strength training on ligament strength
-DJD (osteoarthritis): thinning articular cartilage, thickening compact bone under articular cartilage, possible genetic aging and environmental factors impact DJD development, regular runners do not have greater incidence of osteoarthritis


Articular Cartilage

-hyaline cartilage
-pearly white, partially translucent
-viscoelastic tissue: elastic solid, viscous liquid


Histological Structure of Articular Cartilage

-completely devoid of blood vessels, lymphatic vessels, and nerve fibers
-chondrocytes live normally in immunologic isolation


Histological Structure of Articular Cartilage

-gel matrix: tissue fluid primarily water, collagen, proteoglycans
-cartilage is hydrophilic: fluid can move in and out, gives cartilage its turgidity
-hyaline cartilage has percentage of type II collagen: provides great strength, especially in compression
-proteoglycans are hydrophilic: glue collagen fibers together, provide resillence and elasticity


Histologic Structure of Articular Cartilage

-chondrocytes: produce both collagen and proteoglycans, more metabolically active early in life
-chondrocytes respond to many stimuli: AROM, PROM, hormones, drugs
-Immobilization leads to stasis of synovial fluid, disuse atrophy of cartilage


Articular Cartilage

-creates extremely small coefficient of friction
-motion occurs between two thin fluids rather than surfaces of articular cartilage
-variable thickness
-bundles of collagen fibers form arcades



-exist in knee
-comprised of fibrocartilage rather than hyaline articular cartilage
-provide greater articular joint surface area
-extra-cellular matrix consists of mainly type I collagen



-composed of dense regular connective tissue
-contain an abundance of type I collagen
-have remarkable tensile strength
-neither ligaments nor tendons tear out of bone
-function to connect bone to bone, add to the mechanical stability of joints, help to guide joint motion