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ArticulationsArticulations
A look at the structural and A look at the structural and functional classification of functional classification of joints and the movements joints and the movements
they providethey provide
JointsJoints Rigid elements of the skeleton meet Rigid elements of the skeleton meet
at joints or articulationsat joints or articulations Greek root “arthro” means jointGreek root “arthro” means joint Articulations can be:Articulations can be:
Bone to boneBone to bone Bone to cartilageBone to cartilage Teeth in bony socketsTeeth in bony sockets
Structure of jointsStructure of joints Enables resistance to crushing, tearing, Enables resistance to crushing, tearing,
and other forcesand other forces
Classifications of JointsClassifications of Joints Joints can be classified by function or Joints can be classified by function or
structurestructure Functional classificationFunctional classification – based on – based on
amount of movementamount of movement Synarthroses – Synarthroses –
immovable – common in axial skeletonimmovable – common in axial skeleton Amphiarthroses – Amphiarthroses –
slightly movable – common in axial skeletonslightly movable – common in axial skeleton Diarthroses – Diarthroses –
freely movable – common in appendicular freely movable – common in appendicular skeleton skeleton
Classifications of JointsClassifications of Joints
Structural classificationStructural classification based on: based on: Material that binds bones togetherMaterial that binds bones together Presence or absence of a joint cavityPresence or absence of a joint cavity Structural classifications includeStructural classifications include
FibrousFibrous CartilaginousCartilaginous SynovialSynovial
SynarthrosesSynarthroses
Immovable jointsImmovable joints Do not have a joint cavityDo not have a joint cavity May be Fibrous or CartilagenousMay be Fibrous or Cartilagenous
sutures – i.e. coronal suturesutures – i.e. coronal suture Synchondrosis – epiphyseal platesSynchondrosis – epiphyseal plates Gomphoses – i.e. your teeth!Gomphoses – i.e. your teeth!
Synarthroses: SuturesSynarthroses: Sutures
Bones are tightly Bones are tightly bound by a minimal bound by a minimal amount of fibrous amount of fibrous tissuetissue
Only occur between Only occur between the bones of the skullthe bones of the skull
Allow bone growth so Allow bone growth so that the skull can that the skull can expand with brain expand with brain during childhoodduring childhood
Synarthroses: GomphosesSynarthroses: Gomphoses
Tooth in a Tooth in a socketsocket
Connecting Connecting ligament – the ligament – the periodontal periodontal ligament ligament
Synarthroses: Synarthroses: SynchondrosesSynchondroses
Cartilaginous Synarthritic JointsCartilaginous Synarthritic Joints Joint between first rib and Joint between first rib and
manubriummanubrium
Hyaline cartilage Hyaline cartilage unites bonesunites bones Epiphyseal platesEpiphyseal plates
AmphiarthrosesAmphiarthroses
Slightly movable jointsSlightly movable joints No joint cavityNo joint cavity Amphiarthroses may beAmphiarthroses may be
FibrousFibrous cartilagenouscartilagenous
Amphiarthroses: Amphiarthroses: SyndesmosesSyndesmoses
Fibrous Fibrous Amphiarthritic JointsAmphiarthritic Joints Bones are connected Bones are connected
exclusively by exclusively by ligamentsligaments
Amount of movement Amount of movement depends on length of depends on length of fibersfibers
Amphiarthroses: Amphiarthroses: SymphysesSymphyses
Cartilaginous Amphiarthritic JointCartilaginous Amphiarthritic Joint Fibrocartilage unites bones – resists Fibrocartilage unites bones – resists
tension and compressiontension and compression Slightly movable joints that provide Slightly movable joints that provide
strength with flexibilitystrength with flexibility IntervertebralIntervertebral
discsdiscs Pubic symphysisPubic symphysis
DiarthrosesDiarthroses
Most movable type of jointMost movable type of joint Diarthroses are synovialDiarthroses are synovial
Each contains a fluid-filled joint cavity Each contains a fluid-filled joint cavity called a synovial cavity.called a synovial cavity.
A Typical Synovial JointA Typical Synovial JointFibrous Capsule
Synovial Membrane
Synovial Joint Cavity
Articular Cartilage
Cartilage (Articular) Disc
How Synovial Joints How Synovial Joints FunctionFunction
Synovial joints – lubricating devicesSynovial joints – lubricating devices Friction could overheat and destroy Friction could overheat and destroy
joint tissuejoint tissue Are subjected to compressive forcesAre subjected to compressive forces
Fluid is squeezed out as opposing cartilages Fluid is squeezed out as opposing cartilages touchtouch
Cartilages ride on the slippery filmCartilages ride on the slippery film
Factors Influencing Joint Factors Influencing Joint StabililtyStabililty
Articular surfaces Articular surfaces seldom play a major role in joint stabilityseldom play a major role in joint stability
ExceptionsExceptions: the elbow, the knee and the hip : the elbow, the knee and the hip do provide stabilitydo provide stability
LigamentsLigaments the more ligaments in a joint, the the more ligaments in a joint, the
stronger it isstronger it is Muscle toneMuscle tone
the most important factor in joint stabilitythe most important factor in joint stability keeps tension on muscle tendonskeeps tension on muscle tendons
Movements Allowed by Movements Allowed by Synovial JointsSynovial Joints
Three basic types of movementThree basic types of movement Gliding – one bone across the surface of anotherGliding – one bone across the surface of another Angular movement – movements change the Angular movement – movements change the
angle between bonesangle between bones Rotation – movement around a bone's long axisRotation – movement around a bone's long axis
And a host of “special movements”And a host of “special movements” Supination / PronationSupination / Pronation Dorsiflexion / Plantar flextionDorsiflexion / Plantar flextion Inversion / EversionInversion / Eversion Projection / RetractionProjection / Retraction Elevation / DepressionElevation / Depression OppositionOpposition
Gliding JointsGliding Joints
Flat surfaces of two bones slip across Flat surfaces of two bones slip across each othereach other
Gliding occurs Gliding occurs between between CarpalsCarpals Articular Articular
processes processes of vertebraeof vertebrae
TarsalsTarsals
Angular MovementsAngular Movements Increase or decrease angle between Increase or decrease angle between
bonesbones Movements involve:Movements involve:
Flexion and ExtensionFlexion and Extension Flexion: movement decreases the joint angleFlexion: movement decreases the joint angle Extension: movement that increases the joint Extension: movement that increases the joint
angleangle Abduction and AdductionAbduction and Adduction
Abduction: movement away from midlineAbduction: movement away from midline Adduction: movement towards midlineAdduction: movement towards midline
CircumductionCircumduction Circular motion allowed by a jointCircular motion allowed by a joint
Angular MovementsAngular Movements
Angular MovementsAngular Movements
Angular MovementsAngular Movements
RotationRotation
Involves turning movement of a bone Involves turning movement of a bone around its long axisaround its long axis The only movement allowed between The only movement allowed between
atlas and axis vertebraeatlas and axis vertebrae Occurs at the hip and shoulder jointsOccurs at the hip and shoulder joints
Special MovementsSpecial Movements
SupinationSupination forearm rotates forearm rotates
laterallylaterally& palm faces & palm faces anteriorlyanteriorly
PronationPronation forearm rotates forearm rotates
mediallymedially& palm faces & palm faces posteriorlyposteriorly
Special MovementsSpecial Movements
DorsiflexionDorsiflexion lifting the foot so its superior surface lifting the foot so its superior surface
approaches the shinapproaches the shin Plantar flexionPlantar flexion
depressing the foot – pointing the toes depressing the foot – pointing the toes downwarddownward
Special MovementsSpecial Movements
InversionInversion turning the sole mediallyturning the sole medially
EversionEversion turning the sole laterallyturning the sole laterally
Special MovementsSpecial Movements ProtractionProtraction
nonangular movement of jutting out the nonangular movement of jutting out the jawjaw
RetractionRetraction opposite movement to protraction opposite movement to protraction
Special MovementsSpecial Movements
ElevationElevation lifting a body superiorlylifting a body superiorly
DepressionDepression moving the elevatedmoving the elevated
part inferiorlypart inferiorly
Special MovementsSpecial Movements
OppositionOpposition movement of the thumb to touch the movement of the thumb to touch the
tips of other fingerstips of other fingers
Synovial Joints Classified Synovial Joints Classified by Structureby Structure
Plane jointPlane joint Articular surfaces are Articular surfaces are
flat planesflat planes Short gliding movements Short gliding movements
are allowedare allowed Intertarsal and intercarpal Intertarsal and intercarpal
jointsjoints Movements are Movements are nonaxialnonaxial Gliding does not involve Gliding does not involve
rotation around any axisrotation around any axis Considered a translational Considered a translational
movmentmovment
Synovial Joints Classified Synovial Joints Classified by Structureby Structure
Hinge jointsHinge joints Cylindrical end of one bone Cylindrical end of one bone
fits into a trough on another fits into a trough on another bonebone
Angular movement is allowed Angular movement is allowed in one planein one plane
Elbow, ankle, and joints Elbow, ankle, and joints between phalangesbetween phalanges
Movement is Movement is uniaxialuniaxial – – allows movement around one allows movement around one axis onlyaxis only
Pivot jointsPivot joints Classified as Classified as uniaxialuniaxial
rotating bone only turns rotating bone only turns around its long axisaround its long axis
ExamplesExamples Proximal radioulnar Proximal radioulnar
jointjoint Joint between atlas and Joint between atlas and
axisaxis
Synovial Joints Classified Synovial Joints Classified by Structureby Structure
Synovial Joints Classified Synovial Joints Classified by Structureby Structure
Condyloid (Saddle) Condyloid (Saddle) jointsjoints Allow moving bone to Allow moving bone to
travel:travel: Side to side – Side to side –
abduction-adductionabduction-adduction Back and forth – Back and forth –
flexion-extensionflexion-extension Classified as Classified as biaxialbiaxial
movement occurs movement occurs around two axesaround two axes
Synovial Joints Classified Synovial Joints Classified by Structureby Structure
Saddle jointsSaddle joints Each articular Each articular
surface has surface has concave and convex concave and convex surfacessurfaces
Classified as Classified as biaxialbiaxial joints joints
Synovial Joints Classified Synovial Joints Classified by Structureby Structure
Ball-and-socket jointsBall-and-socket joints Spherical head of one Spherical head of one
bone fits into round bone fits into round socket of anothersocket of another
Classified as Classified as multiaxialmultiaxial – allow – allow movement in all axesmovement in all axes
Examples: shoulder Examples: shoulder and hip jointsand hip joints
General Joint Concerns & General Joint Concerns & IssuesIssues
Structure of joints makes them Structure of joints makes them prone to traumatic stressprone to traumatic stress
Function of joints makes them Function of joints makes them subject to friction and wearsubject to friction and wear
Affected by inflammatory and Affected by inflammatory and degenerative processes degenerative processes
Joint InjuriesJoint Injuries
Sprains – ligaments of a reinforcing Sprains – ligaments of a reinforcing joint are stretched or tornjoint are stretched or torn
Dislocation – occurs when the bones Dislocation – occurs when the bones of a joint are forced out of alignmentof a joint are forced out of alignment Luxation = complete dislocationLuxation = complete dislocation Subluxation = partial dislocationSubluxation = partial dislocation
Torn cartilage – common injury to Torn cartilage – common injury to meniscus of knee jointmeniscus of knee joint
Inflammatory and Degenerative Inflammatory and Degenerative ConditionsConditions
Bursitis – inflammation of a bursa do to Bursitis – inflammation of a bursa do to injury or frictioninjury or friction
Tendonitis – inflammation of a tendon Tendonitis – inflammation of a tendon sheathsheath
Arthritis – describes over 100 kinds of Arthritis – describes over 100 kinds of joint-damaging diseasesjoint-damaging diseases Osteoarthritis – most common type – “wear and Osteoarthritis – most common type – “wear and
tear” arthritistear” arthritis Rheumatoid arthritis – a chronic inflammatory Rheumatoid arthritis – a chronic inflammatory
disorder disorder Gouty arthritis (gout) – uric acid build-up Gouty arthritis (gout) – uric acid build-up
causes pain in jointscauses pain in joints Lyme disease – inflammatory disease often Lyme disease – inflammatory disease often
resulting in joint painresulting in joint pain
Additional Joint Additional Joint InformationInformation
Anatomy of Shoulder, Elbow, Hip & Anatomy of Shoulder, Elbow, Hip & Knee Joints Knee Joints
Selected Synovial Joints - Selected Synovial Joints - ShoulderShoulder
Shoulder (Glenohumeral) joint – Shoulder (Glenohumeral) joint – General CharacteristicsGeneral Characteristics The most freely movable joint – lacks The most freely movable joint – lacks
stabilitystability Articular capsule is thin and looseArticular capsule is thin and loose Muscle tendons contribute to joint Muscle tendons contribute to joint
stabilitystability
Glenohumeral JointGlenohumeral Joint
Selected Synovial JointsSelected Synovial Joints
Elbow joint – General Elbow joint – General CharacteristicsCharacteristics Allows flexion and extensionAllows flexion and extension The humerus’ articulation with ulna The humerus’ articulation with ulna
forms the hingeforms the hinge Tendons of biceps and triceps brachii Tendons of biceps and triceps brachii
provide stabilityprovide stability
Elbow JointElbow Joint
Elbow JointElbow Joint
Selected Synovial JointsSelected Synovial Joints
Hip joint – General CharacteristicsHip joint – General Characteristics A ball-and-socket structureA ball-and-socket structure Movements occur in all axes – limited by Movements occur in all axes – limited by
ligaments and acetabulumligaments and acetabulum Head of femur articulates with Head of femur articulates with
acetabulumacetabulum Muscle tendons contributes to stability, Muscle tendons contributes to stability,
howeverhowever Stability comes chiefly from acetabulum Stability comes chiefly from acetabulum
and capsular ligamentsand capsular ligaments
Frontal Section and Frontal Section and Anterior View of the Hip Anterior View of the Hip
JointJoint
Posterior View of the Hip Posterior View of the Hip JointJoint
Figure 9.13c, d
Selected Synovial JointsSelected Synovial Joints
Knee joint – General CharacteristicsKnee joint – General Characteristics The largest and most complex jointThe largest and most complex joint Primarily acts as a hinge jointPrimarily acts as a hinge joint Has some capacity for rotation when leg Has some capacity for rotation when leg
is flexedis flexed Two fibrocartilage menisci occur within Two fibrocartilage menisci occur within
the joint cavitythe joint cavity
Sagittal Sagittal Section of Section of Knee JointKnee Joint
Superior Superior View of View of
Knee JointKnee Joint
Anterior View of Flexed Anterior View of Flexed KneeKnee