Articulations A look at the structural and functional classification of joints and the movements they provide

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



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


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


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


ElevationElevation lifting a body superiorlylifting a body superiorly

DepressionDepression moving the elevatedmoving the elevated

part inferiorlypart inferiorly


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


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



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


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


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


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


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

Documents

Articulations A look at the structural and functional classification of joints and the movements they provide