JointJoint (( arthrosisarthrosis ,, articulationarticulation ))
RRegionegion inin whichwhich bonesbones areare cappedcapped andand surroundedsurrounded byby connectiveconnective tissuestissues thatthat holdhold thethe bonesbones togethertogether andand determinedetermine thethe typetype andand degreedegree ofof movementmovement betweenbetween themthem SyndesmologySyndesmology–– thethe scientificscientific studystudy ofof ligamentsligaments ArthrologyArthrology–– thethe scientificscientific studystudy ofof jointsjoints TypesTypes ofof jointsjoints
diarthrosdiarthros iiss (synovial(synovial joint)joint) →→ freefree bonebone movementmovement synarthrossynarthros iiss (s(s olidolid ,, nonnon --synovialsynovial jointjoint )) →→ veryvery limitedlimited oror nono movementmovement syndesmosissyndesmosis →→ bonesbones areare linkedlinked byby anan interosseousinterosseous ligamentligament ofof densedense connectiveconnective tissuetissue →→ permitspermits aa certaincertain amountamount ofof movementmovement ssynchondrosynchondros iiss ((synsyn ++ chondroschondros )) →→ bonesbones areare linkedlinked byby hyalinehyaline cartilagecartilage →→ permitspermits aa certaincertain amountamount ofof movementmovement synostosissynostosis ((synsyn ,, togethertogether ++ osteonosteon ++ Gr.Gr. osis,osis, condition)condition) →→ bonesbones linkedlinked byby bonebone tissuetissue →→ nono movementmovement takestakes placeplace Systems of Classifying the Joints SyndesmosisSyndesmosis (fibrous(fibrous joint)joint)
AA collagenouscollagenous (or(or fibroelastic)fibroelastic) junctionjunction betweenbetween bonesbones ClassificationClassification InterosseusInterosseus ligamentligament InterosseusInterosseus membranemembrane SutureSuture GomphosisGomphosis InterosseusInterosseus ligamentligament
the dorsal part of the sacroiliac junction & interosseous ligaments, e.g. the carpus and tarsus InterosseusInterosseus membranemembrane
the interosseous membranes of the forearm and calf SutureSuture
periosteum
Cambial Middle Capsular
Sutures are limited to the skull Margins of bones are separated only by connective tissue (= sutural ligament or membrane ) Layers Cambial → osteogenic cells continuous with the periosteum Capsular → fibrous tissue Middle → loose connective tissue (contains blood vessels ) Types of sutures plane suture – simple apposition (e.g. between maxillae) serrate suture – saw -like (e.g. saggital) squamous – bones overlap (e.g.temporoparietal) GomphosisGomphosis
Restricted to the fixation of teeth in their alveolar sockets in the mandible and maxillae.
The collagen of the periodontium connects dental cement with alveolar bone. SpecialSpecial typetype ofof fibrousfibrous jointjoint -- schindylesisschindylesis
A ridged bone fits into a groove on a neighbouring element, e.g. the cleft between the alae of the vomer, which receives the rostrum of the sphenoid. CartilaginousCartilaginous jointsjoints
AA cartilaginouscartilaginous junctionjunction betweenbetween bonesbones ClassificationClassification primaryprimary cartilaginouscartilaginous jointjoint →→ synchondrossynchondros iiss secondarysecondary cartilaginouscartilaginous jointjoint →→ symphyssymphys iiss
TheThe termsterms primaryprimary andand secondarysecondary areare onlyonly usefuluseful inin thethe instancesinstances ofof certaincertain symphysessymphyses which,which, developmentalldevelopmentally,y, areare precededpreceded byby synchondrosessynchondroses withinwithin whichwhich furtherfurther differentiationdifferentiation occursoccurs SSynchondrosynchondros iiss –– hyalinehyaline cartilagecartilage Two ossifying fronts closely bonded by a specialized hyaline growth cartilage
the rate of ossification of both the rate of ossification of both surfaces is approx. equal → surfaces is unequal → the the growth cartilage has a growth cartilage structure is central quiescent zone asymmetrical (e.g. long bones) equidistant from the surfaces (e.g. crania bones) SSynchondrosynchondros iiss -- occurrenceoccurrence
DuringDuring developmentdevelopment synchondrosessynchondroses areare primarilyprimarily growthgrowth mechanismsmechanisms →→ thethe cartilagecartilage isis aa templatetemplate ofof thethe developingdeveloping bonebone andand eventuallyeventually disappearsdisappears SSynchondrosesynchondroses remainingremaining inin adulthoodadulthood SSternocostalternocostal jointjoint -- betweenbetween thethe sternumsternum andand firstfirst ribrib PPetrobasilaretrobasilar jointjoint -- betweenbetween thethe petrouspetrous portionportion ofof thethe temporaltemporal bonebone andand thethe basilarbasilar partpart ofof thethe occipitaloccipital bonebone SternocostalSternocostal jointsjoints
Rib I Rib I SSymphysymphys iiss -- fibrocartilagefibrocartilage
AA piecepiece ofof fibrocartilagefibrocartilage betweenbetween thethe flatflat surfacessurfaces ofof twotwo bonesbones (tremendous(tremendous pressure)pressure) →→ allall symphysessymphyses areare medianmedian ttopographicallyopographically CollagenousCollagenous ligamentsligaments extendextend fromfrom thethe periosteperioste umum acrossacross thethe symphysissymphysis andand blendblend withwith thethe perichondriperichondriumum TheThe capsulecapsule isis incompleteincomplete butbut likelike synovialsynovial jointsjoints itit containcontain ss plexusesplexuses ofof afferentafferent nervenerve terminalsterminals SSymphysymphys iiss -- occurrenceoccurrence
IntervertebralIntervertebral disksdisks PubicPubic symphysissymphysis MManubriosternalanubriosternal -- betweenbetween manubriummanubrium andand sternalsternal bodybody SSymphysymphys iiss -- intervertebralintervertebral disksdisks
Intervertebral symphyses (presacral), displaying age-related changes. Partial or complete synostosis is the normal fate of sacral and coccygeal symphyses. IntervertebralIntervertebral diskdisk
annulus fibrosus : dense connective tissue + overlapping laminae of fibrocartilag e Nucleus pulposus (collagen type I) nucleus pulposus : a few rounded cells embedded in a viscous matrix rich in hyaluronic acid and type II collagen fibril s SynostosisSynostosis --
SynostosisSynostosis isis thethe normalnormal fatefate ofof almostalmost allall synchondrosessynchondroses whenwhen endochondralendochondral growthgrowth hashas ceasedceased SSkullkull && pelvicpelvic bonesbones inin adulthoodadulthood
newborn adolescent
Blue = unossified (cartilaginous) regions SynovialSynovial jointsjoints
AAccommodateccommodate thethe movementmovement ofof bonesbones andand minimizeminimize thethe frictionfriction betweenbetween themthem TThehe osseousosseous surfacessurfaces involvedinvolved areare notnot inin continuitycontinuity bonybony surfacessurfaces areare coveredcovered byby articulararticular cartilagecartilage contactcontact isis strictlystrictly limitedlimited betweenbetween cartilagcartilag ee sslidingliding contactcontact isis facilitatedfacilitated byby viscousviscous fluidfluid →→ lubricantlubricant ComponentsComponents ofof synovialsynovial jointsjoints
Articular cartilage : covers the bony parts forming the joint Synovial capsule Fibrous layer - dense connective tissue, continuous with the periosteum Synovial layer ( = synovial membrane) - covers all nonarticular surfaces Articular cavity - contains a high concentration of hyaluronic acid and the glycoprotein lubricin combined with filtrate of plasma Articular ligaments SectionSection throughthrough kneeknee jointjoint ArticularArticular cartilagecartilage
Hyaline cartilage with no perichondrium The collagen fibers of the articular surface cartilage are arranged to distribute the forces generated by pressure in this tissue No nerves or blood vessels → nutrition depend s on a vascular The collagen fibers of the cartilage are arranged as plexus in the synovial membrane gothic arches and synovial fluid SynovialSynovial capsulecapsule
Fibrous layer - dense connective tissue, continuous with the periosteum Synovial layer ( = synovial membrane) - covers all nonarticular surfaces There is no basal lamina between the lining cells and the underlying connective tissue This tissue is rich in blood capillaries and contains a variable number of adipose cells (AD) CellsCells ofof thethe synovialsynovial layerlayer
Type A cells are macrophages responsible for removing debris from the joint space Type B cells resemble (Type A cells ) fibroblasts → secrete the synovial fluid There is no basal lamina between the lining cells and the underlying connective tissue
Synovial cells do not divide (Type B cells ) actively in normal synovial membranes. Their division rate increases dramatically in response to acute trauma and haemarthrosis ArticularArticular (synovial)(synovial) cavitycavity
Hermetically closed Synovia: Filled with synovia (fluid) syn - together ovi – egg (-white) glucose protein hyaluronic acid Clear, yellowish, viscous fluid, containing cells (fibroblast -like cells, monocytes, lymphocytes) In some joints lined on the outside with s mall, pillow -like, flaccid sacs → bursa → reduce friction of tendons tendon sheath → bursa wrapped around a tendon Exercise and Articular Cartilage When synovial fluid is warmed by exercise, it becomes thinner (less viscous) and more easily absorbed by the articular cartilage. The cartilage then swells and provides a more effective cushion against compression. For this reason, a warm-up period before vigorous exercise helps protect the articular cartilage from undue wear and tear.
Because cartilage is nonvascular, its repetitive compression during exercise is important to its nutrition and waste removal. Each time a cartilage is compressed, fluid and metabolic wastes are squeezed out of it. When weight is taken off the joint, the cartilage absorbs synovial fluid like a sponge, and the fluid carries oxygen and nutrients to the chondrocytes. Lack of exercise causes the articular cartilages to deteriorate more rapidly from lack of nutrition, oxygenation, and waste removal. ArticularArticular ligamentsligaments
Meniscus: men - moon iscus - little
All synovial joints are reinforced by connective tissue ligaments → placed to resist motion in undesirable directions extrinsic (= extracapsular ) ligaments intrinsic (= intracapsular ) ligaments Have a minimal blood supply and are slow to heal Articular meniscus - an ingrowth of the fibrous capsule between the articular cartilage s of the bone → provide additional cushioning of the cartilage Other – articular labrum ( fibrocartilaginous a nnular lip ), articular disc SynovialSynovial jointsjoints cancan bebe classifiedclassified basedbased onon
numbernumber ofof surfacessurfaces shapeshape ofof surfacessurfaces number of planes in space (x, y, z), in which they move TypesTypes ofof synovialsynovial jointsjoints basedbased onon numbernumber ofof surfacesurfacess
2 articular surfaces contains an intra-articular disc or meniscus more than 2 articular surfaces
Humerus
Ulna R TypesTypes ofof synovialsynovial jointsjoints basedbased onon shapeshape ofof surfacessurfaces
hemispherical head fits projection of a bone fits into a into a cuplike depression ringlike ligament of another bone
(nearly) flat bones slide convex surface fits into a over each other concave depression
2 surfaces shaped convex surface fits in like a saddle elliptical depression TypesTypes ofof synovialsynovial jointsjoints basedbased onon number of planes
Monaxial – the bone can move in only one plane Biaxial – the bone can move can move in two planes Multiaxial – the bone can move can move in three planes FeaturesFeatures ofof variousvarious typestypes ofof synovialsynovial jointsjoints
Ball-and-socket – multiaxial; shoulder and hip joints
Hinge – monaxial; elbow, knee, and interphalangeal joints
Saddle – biaxial; trapeziometacarpal joint, allows thumb opposition
Pivot – monaxial; atlantoaxial and proximal radioulnar joints
Gliding – monaxial; intercarpal, intertarsal, and sternoclavicular joints; joints between the articular processes of the vertebrae
Condyloid (ellipsoid) – biaxial; radiocarpal and metacarpophalangeal joints PrincipalPrincipal movementsmovements ofof diarthrosesdiarthroses Angulation flexion-extension abduction-adduction axial rotation
gliding Principal Diarthroses Temporomandibular
Humeroscapular
Elbow
Coxal
Knee
Ankle ArthroscopyArthroscopy JointJoint diseasedisease -- rheumatoidrheumatoid arthritisarthritis
Proliferating synovium extends into the joint space, burrows into the bone beneath the articular cartilage, and covers the cartilage
The articular cartilage is destroyed
ankylosis Joint is destroyed and becomes fused (=ankylosis)
ankylosis
Essentials of Rubin's Pathology, 5th Edition JointJoint diseasedisease -- osteoarthrosisosteoarthrosis
Chandrasoma & Taylor, Concise Pathology 3rd Ed JointJoint prosthesesprostheses