150 ch8 joints

Anatomy and Physiology, Seventh EditionRod R. Seeley Idaho State UniversityTrent D. Stephens Idaho State UniversityPhilip Tate Phoenix CollegeCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.Chapter 08Lecture Outline*

Articulations or Joints

Articulation or JointPlace where two bones (or bone and cartilage) come togetherArthrology = study of the jointsKinesiology = study of musculoskeletalFunctions of jointsGive the skeleton mobilityHold the skeleton togetherStructure correlated with movement

Classification of JointsStructural classes: based on type of connective tissue type that binds bones and whether or not a joint cavity is presentFibrousCartilaginousSynovialFunctional classes: based on degree of motion Synarthrosis: non-movableAmphiarthrosis: slightly movableDiarthrosis: freely movable

Fibrous JointsCharacteristicsUnited by fibrous connective tissueHave no joint cavityMove little or noneTypes: SuturesSyndesmosesGomphoses

Fibrous Joints: Sutures Types of suturesSerrated: Opposing bones interdigitate (Sagittal suture)Lap: Overlapping beveled edges (Squamosal suture) Plane: Straight, non-overlapping edges (Intermaxillary suture) Periosteum of one bone is continuous with the periosteum of the other.In adults may ossify completely: synostosis. Fontanels: membranous areas in the suture between bones. Allow change in shape of head during birth and rapid growth of the brain after birth.

Types of Sutures

Fibrous Joints: SyndesmosesTwo bones joined by ligamentInterosseous membraneMost moveable of fibrous jointsExamples: radioulnar joint and tibiofibular joints

Fibrous Joints: GomphosesSpecialized jointsPegs that fit into socketsPeriodontal ligaments: hold teeth in placeInflammationsGingivitis leads toPeriodontal disease

Cartilaginous JointsBones are joined by cartilageLack a joint cavityTypesSynchondroses: bound by hyaline cartilageSymphyses: bound by fibrocartilage

Cartilaginous Joints: SynchondrosesJoined by hyaline cartilageLittle or no movementSome are temporary and are replaced by synostosesSome are permanentSome like costochondral joints develop into synovial jointsExamples: Epiphyseal plates, 1st sternocostal

Cartilaginous Joints: SymphysesFibrocartilage uniting two bonesSlightly movableExamples: symphysis pubis, between the manubrium and the body of the sternum, intervertebral disks.

Synovial JointsContain synovial fluid in a joint cavity called the synovial cavityAllow considerable movement (diarthroses)Most joints that unite bones of appendicular skeleton reflecting greater mobility of appendicular skeleton compared to axial

Structure of Synovial JointsArticular cartilage: hyaline; provides smooth surface on epiphysisJoint cavity: synovial; encloses articular surfacesArticular Capsule encloses joint cavityFibrous capsule: dense irregular connective tissuecontinuous with periosteum. Portions may thicken to form ligaments.Synovial membrane and fluid:Thin, delicate membrane lines inside of joint capsule. Synovial fluid: complex mixture of polysaccharides, proteins, fat and cells. Hyaluronic acid- slippery. No blood vessels or nerves in articular cartilages; nutrients derived from nearby blood vessels and synovial fluidNerves in capsule help brain know position of joints (proprioception)

Accessory StructuresBursaePockets of synovial membrane and fluid that extend from the joint. Found in areas of frictionBursitisLigaments and tendons: stabilizationArticular discs: temperomandibular, sternoclavicular, acromioclavicularMenisci: fibrocartilaginous pads in the knee.Tendon sheaths: synovial sacs that surround tendons as they pass near or over bone

Synovial Joints: Friction-Reducing StructuresFigure 8.4

Types of MovementGliding: in plane joints; slight movementAngularFlexion and ExtensionHyperextensionPlantar and DorsiflexionAbduction and AdductionCircularRotationPronation and SupinationCircumduction

Flexion and ExtensionFlexion: movement of a body part anterior to the coronal planeExtension: movement of a body part posterior to the coronal plane

Dorsiflexion and Plantar FlexionExceptions to definitionPlantar flexion: standing on the toesDorsiflexion: foot lifted toward the shin

Abduction and AdductionAbduction: movement away from the midlineAdduction: movement toward the midline

Circular Movements: Rotation, Pronation and SupinationRotation: turning of a structure on its long axisExamples: rotation of the head, humerus, entire bodyMedial and lateral rotation; example, the rotation of the armPronation/Supination: refer to unique rotation of the forearmPronation: palm faces posteriorlySupination: palm faces anteriorly

Circular Movement: CircumductionCombination of flexion, extension, abduction, adductionAppendage describes a cone

Special MovementsUnique to only one or two jointsTypesElevation and DepressionProtraction and RetractionExcursionOpposition and RepositionInversion and Eversion

Elevation and DepressionElevation: moves a structure superiorDepression: moves a structure inferiorExamples: shrugging the shoulders, opening and closing the mouth

Protraction and RetractionProtraction: gliding motion anteriorlyRetraction: moves structure back to anatomic position or even further posteriorlyExamples: scapulae and mandibles

ExcursionLateral: moving mandible to the right or left of midlineMedial: return the mandible to the midline

Opposition and RepositionOpposition: movement of thumb and little finger toward each otherReposition: return to anatomical position

Inversion and EversionInversion: turning the ankle so the plantar surface of foot faces mediallyEversion: turning the ankle so the plantar surface of foot faces laterally

Movements at Synovial jointsMonoaxial: occurring around one axisBiaxial: occurring around two axes at right angles to each otherMultiaxial: occurring around several axesSee Table 8.2 in text

Types of Synovial Joints:Plane JointsPlane or gliding jointsMonaxial. One flat bone surface glides or slips over another similar surfaceSometimes considered an amphiarthrosisExamples: intervertebral, intercarpal, intertarsal acromioclavicular, carpometacarpal, tarsometatarsal,

Hinge and Pivot JointsHinge jointsMonaxialConvex cylinder in one bone; corresponding concavity in the otherExample: elbow, ankle, interphalangealPivot jointsMonaxial. Rotation around a single axis.Cylindrical bony process rotating within a circle of bone and ligamentExample: articulation between dens of axis and atlas (atlantoaxial), proximal radioulnar

Saddle joints Each articular surface is shaped like a saddle; Trapeziometacarpal joint at base of the thumb

Types of Synovial Joints:

Ball-and-Socket and Ellipsoid JointsBall-and-socketSmooth heispherical head fits within a cuplike depressionMultiaxialExamples: shoulder and hip jointsCondyloid (ellipsoid) jointOval convex surface on one bone fits into a similarly shaped depression on the nextAtlantooccipital joint (C1-C2)Metacarpophalangeal joints

Shoulder (Glenohumeral) JointMost freely moveable joint in bodyShallowness and loosenessStability is reducedDeepened by glenoid labrum, a rim of cartilage built up around glenoid cavitySupported by rotator cuff musculaturetendons fuse to joint capsule Stabilize and strengthen itsupraspinatus, infraspinatus, teres minor and subscapularis,Bursae: subacromial and subscapularTendon of biceps brachii passes through the joint capsuleFlexion/extension, abduction/adduction, rotation, circumduction

Tendons of Rotator Cuff Muscles

The Knee JointMost complex diarthrosis patellofemoral = gliding jointtibiofemoral = gliding with slight rotation and gliding possible in flexed positionJoint capsule anteriorly consists of patella and extensions of quadriceps femoris tendonCapsule strengthened by extracapsular and intracapsular ligaments

Knee, cont.Cruciate ligaments: extend between intercondylar eminence of tibia and fossa of the femurAnterior cruciate ligament (ACL). Prevents anterior displacement of tibiaPosterior cruciate ligament (PCL). Prevents posterior displacement of tibiaCollateral and popliteal ligaments: along with tendons of thigh muscles strengthen the jointBursae: may result in slow accumulation of fluid in the joint (water on the knee)

Knee Joint Anterior and Posterior ViewsAnterior and lateral cruciate ligaments limit anterior and posterior sliding movementsMedial and lateral collateral ligaments prevent rotation of extended knee

Knee Joint Superior ViewMedial and lateral meniscus absorb shock and shape joint

Knee Injuries and DisordersFootball injuries: often tear the tibial collateral ligament, the anterior cruciate ligament, and damage the medial meniscus BursitisChondromalacia: softening of cartilage due to abnormal movement of the patella or to accumulation of fluid in fat pad posterior to patellaHemarthrosis: acute accumulation of blood in joint

Effects of Aging on JointsTissue repair slows; rate of new blood vessel development decreasesArticular cartilages wear down and matrix becomes more rigidProduction of synovial fluid declinesLigaments and tendons become shorter and less flexible: decrease in range of motion (ROM)Muscles around joints weakenA decrease in activity causes less flexibility and decreased ROM

SprainsThe ligaments reinforcing a joint are stretche