Articulations/ Joints

Mousavi SJ Kinesiology course_ 3rd session_ 27 Bahman

Force components

Articulations

Wherever two bones interact

Function depends on structure

PermitNo movement

Slight movement

Extensive movement

SynarthrosesImmovable joints

AmphiarthrosesSlightly movable joints

DiarthrosesFreely movable joints

Three categories based on range of motion

Synarthroses

Bony edges may interlock

SuturesBetween skull bones

GomphosisBetween teeth and jaw

SynchondrosisEpiphyseal plate

SynostosisFused bones

Amphiarthroses

Limited movements

SyndesmosisCollagen fibers connect bones

SymphysisBones are separated by cartilage pad

Synarthrodial or Fibrous Joints

Little or no movementfound in sutures of skull

syndesmoses - dense fibrous tissues that allow very limited movement - at coracroacromial, midradioulnar joints

Amphiarthroses

Slightly movable“Amphi” = both sides

permit slightly more movement than Synarthrodial joints

Sychondroses - held together by hyaline cartilage (sternocostal joints)

Amphiarthroses

Symphysesthin plates of hyaline cartilage separate a disc of fibrocartilage from the bones

vertebral joints and pubic symphysis

Diarthroses (synovial joints)

Wide range of movementBony surfaces covered by articular cartilageLubricated by synovial fluidEnclosed with joint capsuleAccessory structures

MenisciFat padsLigamentsTendonsBursaeTendon sheaths

Figure 8.1a Structure of a Synovial Joint

Synovial joints are diarthrotic joints that permit a wide range of motion.

Figure 8.1b Structure of a Synovial Joint

Diarthrodial joint

Cartilageknown as hyaline cartilage

no direct blood supply “avascular”

60-80% water

collagen & proteoglycan gel

viscoelastic

Diarthrodial Joint

Cartilagevaries in thickness depending on joint

thick on knee, thin on ankle

Meniscus• fibrocartilage -

improved fit, stability, load transmission

Diarthrodial joint

Capsulesurrounds joint, fibrous, made mainly of collagen

contains a vacuum

thickenings = ligaments

contains synovial fluid

Figure 8.2 A Simple Model of Articular Motion

Joint Description

Number of axes along which movement is permitted

Monaxial

Biaxial

Triaxial

Diarthrodial Joints

HingeNumber of axes: uniaxial (1) Plane/axis: Sagittal Movements: flexion/extensionMovement limited to 1 plane. e.g. elbow, knee, fingers.

This classification scheme is based on the amount of movement permitted.

Figure 8.6a, b A Structural Classification of Synovial Joints

Diarthrodial Joints

Pivot Number of Axes: uniaxial (1) Plane/Axis: Horizontal planeMovements: Rotatione.g. atlas rotating against axis, head of radius rotating against ulna.

Figure 8.6c, d A Structural Classification of Synovial Joints

Diarthrodial Joints

Ball and Socket Joint Number of axes: triaxial (3) Plane/Axis: sagittal; frontal; horizontalMovements: flex/ext, abd/add, rotation, horiz. abd/add, circum.

Figure 8.6e, f A Structural Classification of Synovial Joints

Diarthrodial Joints

Plane or Gliding Joint (arthrodial)

Only movement is gliding (nonaxial) - articular surfaces are flatintermetatarsal, intercarpal, intertarsal, facet joints of vertebrae

Diarthrodial Joints

Hinge (ginglymus)one surface is convex, other concave

strong collateral ligamnts restrict movement to one plane

elbow (ulnohumeral),inter-phalangeal joints

Diarthrodial Joints

Pivot (screw, trochoid)

rotation is around one axis

atlantoaxial, proximal distal radio-ulnar joints

Diarthrodial Joints

Condyloid (ovoid, ellipsoidal)

one surface is oval convex, other is oval concave

flexion, extension, ab-adduction, circumduction

2nd-5th metacarpophalangeal joints, radio-carpal

Diarthrodial Joints

Saddle (sellar)both articular surfaces are shaped like a riding saddle

like condyloid but with great ROM

thumb (carpometacarpal joint)

Diarthrodial Joints

Ball and Socket (spheroidal)

one surface is concave, other convex

rotation in all three planes is permitted

hip, shoulder

Extremity and Spinal Joints

Describing dynamic motion

Linear motionBack and forth

Angular motionAngle between shaft and surface changes

RotationSpinning of shaft on longitudinal axis

Types of Movement

Angular motion can be described asAbductionAdductionFlexionExtensionHyperextensionCircumduction

Figure 8.4 Rotational Movements

Special movement terms

Eversion/Inversion

Dorsiflexion/Plantar flexion

Lateral flexion

Opposition

Protraction/retraction

Elevation/depression

Figure 8.5a, b Special Movements

Examples of special terms used to describe movement at specific joints or unique directions of movement.

Figure 8.5c-f Special Movements

Structural Classification of Synovial Joints

Gliding jointsLimited movement in single plane

Hinge joint and pivot jointMonaxial

Ellipsoidal joint and saddle jointBiaxial

Ball and socket jointTriaxial

Representative ArticulationsIntervertebral Articulations

Glenohumoral Joint

Elbow Joint

Wrist and hand

Hip

Knee

Ankle

Intervertebral ArticulationsArticular processes of adjacent vertebrae

Symphyseal joints at bodies

Intervertebral discs separate

Nucleus pulposus

Annulus fibrosus

Ligaments bind vertebrae

Permits flexion, extension, lateral flexion, rotation

Damage to the Intervertebral Discs

Shoulder JointGlenohumoral joint

Glenoid fossa and head of humerus

Loose shallow jointGreatest range of motionStrength and stability are

sacrificed

Supported by ligaments and musclesMany bursae

Shoulder Joint (within the capsule)

Hinge jointFlexion and extensionIncludes humeroulnar joint and humeroradial jointSupported by

Radial and ulnar collateral ligamentsAnnular ligaments

The Elbow Joint

Joints of the Wrist and HandCarpometacarpal jointsMetacarpo- phalangeal jointsInterphalangeal joints

proximaldistal

The Hip Joint

Ball and socket diarthrosis

Acetabulum of os coxae and head of femur

Flexion / extension

Adduction / abduction

Circumduction

Rotation

Hip Joint Reinforcements

Iliofemoral ligament

Pubofemoral ligament

Ischiofemoral ligament

Transverse acetabular ligaments

Ligament of femoral head

Hip joint and supporting ligaments

Hip joint and supporting ligaments

Figure 8.15a Articular Structure of the Hip Joint

Coronal sectional views of the hip joint.

The Knee Joint

Complex hinge joint

Resembles three separate jointsMedial condyles of femur and tibia

Lateral condyles of femur and tibia

Patella and patellar surface of femur

Flexion / extension

Limited rotation

The Knee Joint

Support is not a single unified capsuleNot a single fluid cavity

Fibrocartilage pads

Medial and lateral menisci

Fat pads

Seven major ligaments bind knee jointPopliteals

Patellar

Anterior and posterior cruciates

Tibial and fibular collaterals

Knee (Superficial Layer)

Knee (anterior, deep layer)

Knee (posterior, deep layer)

Knee (sagittal view)

The Joints of the Ankle and Foot

Hinge joint

Inferior surface of tibia, lateral malleolus of fibula, trochlea of talus

Primary joint is tibiotalar

Stabilizing ligaments

Dorsiflexion / plantar flexion

Foot Joints

Intertarsal jointsGliding

Tarsometatarsal jointsGliding

MetatarsophalangealGliding

InterphanagealHinge

Foot Joints

Figure 8.19c Joints of the Ankle and Foot (lateral view)

Figure 8.19c Joints of the Ankle and Foot, Part II (medial view)

Joint problems are common with age

Rheumatism General pain and stiffness

ArthritisRheumatic diseases that affect synovial joints

Osteoarthritis: Breakdown of bone and cartilaginous tissue