Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 1 Chapter 9 Articulations

Slide 1Mosby items and derived items © 2007, 2003 by Mosby, Inc.

Chapter 9Chapter 9ArticulationsArticulations


IntroductionIntroduction

• Articulation—point of contact between bonesArticulation—point of contact between bones

• Joints are mostly very movable, but others Joints are mostly very movable, but others are immovable or allow only limited motionare immovable or allow only limited motion

• Movable joints allow complex, highly Movable joints allow complex, highly coordinated, and purposeful movements to be coordinated, and purposeful movements to be executedexecuted


Classification of JointsClassification of Joints

• Joints may be classified using a structural or Joints may be classified using a structural or functional scheme (Table 9-1)functional scheme (Table 9-1)

Structural classification—joints are named Structural classification—joints are named according to one of the following:according to one of the following:

• Type of connective tissue that joins bones together Type of connective tissue that joins bones together (fibrous or cartilaginous joints)(fibrous or cartilaginous joints)

• Presence of a fluid-filled joint capsule (synovial joint)Presence of a fluid-filled joint capsule (synovial joint)



• Joints may be classified (cont.) Joints may be classified (cont.)

Functional classification—joints are named Functional classification—joints are named according to degree of movement allowed:according to degree of movement allowed:

• Synarthroses—immovable jointSynarthroses—immovable joint

• Amphiarthroses—slightly movableAmphiarthroses—slightly movable

• Diarthroses—freely movableDiarthroses—freely movable



• Fibrous joints (synarthroses)—bones of joints Fibrous joints (synarthroses)—bones of joints fit together closely, allowing little or no fit together closely, allowing little or no movement (Figure 9-1)movement (Figure 9-1)

Syndesmoses—joints in which ligaments connect Syndesmoses—joints in which ligaments connect two bonestwo bones

Sutures—found only in skull; toothlike projections Sutures—found only in skull; toothlike projections from adjacent bones interlock with each otherfrom adjacent bones interlock with each other

Gomphoses—between root of a tooth and the Gomphoses—between root of a tooth and the alveolar process of the mandible or maxillaalveolar process of the mandible or maxilla



• Cartilaginous joints (amphiarthroses)—Cartilaginous joints (amphiarthroses)—bones of joints are joined together by hyaline bones of joints are joined together by hyaline cartilage or fibrocartilage; allow very little cartilage or fibrocartilage; allow very little motion (Figure 9-2)motion (Figure 9-2)

Synchondroses—hyaline cartilage present Synchondroses—hyaline cartilage present between articulating bonesbetween articulating bones

Symphyses—joints in which a pad or disk of Symphyses—joints in which a pad or disk of fibrocartilage connects two bonesfibrocartilage connects two bones



• Synovial joints (diarthroses)—freely movable Synovial joints (diarthroses)—freely movable joints (Figure 9-3)joints (Figure 9-3) Structures of synovial jointsStructures of synovial joints

• Joint capsule—sleevelike casing around ends of bones, Joint capsule—sleevelike casing around ends of bones, binding them togetherbinding them together

• Synovial membrane—lines joint capsule and also Synovial membrane—lines joint capsule and also secretes synovial fluidsecretes synovial fluid

• Articular cartilage—hyaline cartilage covering articular Articular cartilage—hyaline cartilage covering articular surfaces of bonessurfaces of bones



Structures of synovial joints (cont.)Structures of synovial joints (cont.)

• Joint cavity—small space between the articulating surfaces of Joint cavity—small space between the articulating surfaces of the two bones of the jointthe two bones of the joint

• Menisci (articular disks)—pads of fibrocartilage located Menisci (articular disks)—pads of fibrocartilage located between articulating bonesbetween articulating bones

• Ligaments—strong cords of dense, white, fibrous tissue that Ligaments—strong cords of dense, white, fibrous tissue that hold bones of synovial joint more firmly togetherhold bones of synovial joint more firmly together

• Bursae—synovial membranes filled with synovial fluid; cushion Bursae—synovial membranes filled with synovial fluid; cushion joints and facilitate movement of tendonsjoints and facilitate movement of tendons



Types of synovial joints (Figure 9-4)Types of synovial joints (Figure 9-4)

• Uniaxial joints—synovial joints that permit movement Uniaxial joints—synovial joints that permit movement around only one axis and in only one planearound only one axis and in only one plane

Hinge joints—articulating ends of bones form a hinge-Hinge joints—articulating ends of bones form a hinge-shaped unity that allows only flexion and extensionshaped unity that allows only flexion and extension

Pivot joints—a projection of one bone articulates with a ring Pivot joints—a projection of one bone articulates with a ring or notch of another boneor notch of another bone



Types of synovial joints (cont.)Types of synovial joints (cont.)

• Biaxial joints—synovial joints that permit movements Biaxial joints—synovial joints that permit movements around two perpendicular axes in two perpendicular around two perpendicular axes in two perpendicular planesplanes

Saddle joints—synovial joints in which the articulating ends Saddle joints—synovial joints in which the articulating ends of the bones resemble reciprocally shaped miniature of the bones resemble reciprocally shaped miniature saddles; only occurrence in body is in thumbssaddles; only occurrence in body is in thumbs

Condyloid (ellipsoidal) joints—synovial joints in which a Condyloid (ellipsoidal) joints—synovial joints in which a condyle fits into an elliptical socketcondyle fits into an elliptical socket



Types of synovial joints (cont.)Types of synovial joints (cont.)

• Multiaxial joints—synovial joints that permit movements Multiaxial joints—synovial joints that permit movements around three or more axes in three or more planesaround three or more axes in three or more planes

Ball and socket (spheroid) joints—most movable joints; Ball and socket (spheroid) joints—most movable joints; ball-shaped head of one bone fits into a concave ball-shaped head of one bone fits into a concave depressiondepression

Gliding joints—relatively flat articulating surfaces that allow Gliding joints—relatively flat articulating surfaces that allow limited gliding movements along various axeslimited gliding movements along various axes


Representative Synovial JointsRepresentative Synovial Joints

• Humeroscapular joint (Figure 9-5) Humeroscapular joint (Figure 9-5)

Shoulder jointShoulder joint

Most mobile joint because of the shallowness Most mobile joint because of the shallowness of the glenoid cavityof the glenoid cavity

Glenoid labrum—narrow rim of fibrocartilage Glenoid labrum—narrow rim of fibrocartilage around glenoid cavity that lends depth to the cavityaround glenoid cavity that lends depth to the cavity

Structures that strengthen the shoulder joint are Structures that strengthen the shoulder joint are ligaments, muscles, tendons, and bursaeligaments, muscles, tendons, and bursae



• Elbow joint (Figure 9-6)Elbow joint (Figure 9-6)

Humeroradial joint—lateral articulation of Humeroradial joint—lateral articulation of capitulum of humerus with head of radiuscapitulum of humerus with head of radius

Humeroulnar joint—medial articulation of trochlea Humeroulnar joint—medial articulation of trochlea of humerus with trochlear notch of ulnaof humerus with trochlear notch of ulna

Both components of elbow joint surrounded by Both components of elbow joint surrounded by single joint capsule and stabilized by collateral single joint capsule and stabilized by collateral ligamentsligaments



• Elbow joint (cont.)Elbow joint (cont.) Classic hinge jointClassic hinge joint

Medial and lateral epicondyles are externally Medial and lateral epicondyles are externally palpable bony landmarkspalpable bony landmarks

Olecranon bursa independent of elbow joint spaceOlecranon bursa independent of elbow joint space—inflammation called olecranon bursitis—inflammation called olecranon bursitis

• Trauma to nerve results in unpleasant sensations in Trauma to nerve results in unpleasant sensations in those fingers and part of hand supplied by nerve; severe those fingers and part of hand supplied by nerve; severe injury may cause “wrist drop”injury may cause “wrist drop”



• Proximal radioulnar joint—between head of radius Proximal radioulnar joint—between head of radius and medial notch of ulnaand medial notch of ulna

Stabilized by annular ligamentStabilized by annular ligament

Permits rotation of forearmPermits rotation of forearm

Dislocation of radial head called “pulled elbow”Dislocation of radial head called “pulled elbow”

• Distal radioulnar joint—point of articulation between Distal radioulnar joint—point of articulation between ulnar notch of radius and head of ulnaulnar notch of radius and head of ulna

Together with proximal radioulnar joint, permits pronation Together with proximal radioulnar joint, permits pronation and supination of forearmand supination of forearm



• Radiocarpal (wrist) joints (Figure 9-7)Radiocarpal (wrist) joints (Figure 9-7)

Only radius articulates directly with carpal bones Only radius articulates directly with carpal bones distally (scaphoid and lunate)distally (scaphoid and lunate)

Joints are synovialJoints are synovial

Scaphoid bone is fractured frequentlyScaphoid bone is fractured frequently

Portion of fractured scaphoid may become Portion of fractured scaphoid may become avascularavascular



• Intercarpal joints (Figure 9-7)Intercarpal joints (Figure 9-7)

Between 8 carpal bonesBetween 8 carpal bones

Stabilized by numerous ligamentsStabilized by numerous ligaments

Joint spaces usually communicateJoint spaces usually communicate

Movements generally gliding, with some Movements generally gliding, with some abduction and flexionabduction and flexion



• Carpometacarpal joints—total of three jointsCarpometacarpal joints—total of three joints One joint for thumb—wide range of movementsOne joint for thumb—wide range of movements

Two joints for fingers—movements largely gliding typeTwo joints for fingers—movements largely gliding type

Thumb carpometacarpal joint is unique and important functionallyThumb carpometacarpal joint is unique and important functionally

• Loose-fitting joint capsuleLoose-fitting joint capsule

• Saddle-shaped articular surfaceSaddle-shaped articular surface

• Movements—extension, adduction, abduction, circumduction, and Movements—extension, adduction, abduction, circumduction, and oppositionopposition

• Opposition—ability to touch tip of thumb to tip of other fingers—Opposition—ability to touch tip of thumb to tip of other fingers—movement of great functional significancemovement of great functional significance



• Metacarpophalangeal joints (Figure 9-8)Metacarpophalangeal joints (Figure 9-8)

Rounded heads of metacarpals articulate with Rounded heads of metacarpals articulate with concave bases of proximal phalangesconcave bases of proximal phalanges

Capsule surrounding joints strengthened by Capsule surrounding joints strengthened by collateral ligaments collateral ligaments

Primary movements are flexion and extensionPrimary movements are flexion and extension



• Interphalangeal jointsInterphalangeal joints

Typical diarthrotic, hinge-type, synovial jointsTypical diarthrotic, hinge-type, synovial joints

Occur between heads of phalanges and bases Occur between heads of phalanges and bases of more distal phalangesof more distal phalanges

Two categories:Two categories:

• PIP joints—proximal interphalangeal joints PIP joints—proximal interphalangeal joints (between proximal and middle phalanges)(between proximal and middle phalanges)

• DIP joints—distal interphalangeal joints DIP joints—distal interphalangeal joints (between middle and distal phalanges)(between middle and distal phalanges)



• Hip joint (Figure 9-9)Hip joint (Figure 9-9) Stable joint because of shape of head of femur and of Stable joint because of shape of head of femur and of

acetabulumacetabulum

A joint capsule and ligaments contribute to joint’s stabilityA joint capsule and ligaments contribute to joint’s stability

• Knee joint (Figures 9-10 and 9-11)Knee joint (Figures 9-10 and 9-11) Largest and one of most complex and most frequently Largest and one of most complex and most frequently

injured jointsinjured joints

Tibiofemoral joint is supported by a joint capsule, cartilage, Tibiofemoral joint is supported by a joint capsule, cartilage, and numerous ligaments and muscle tendonsand numerous ligaments and muscle tendons

Permits flexion and extension and, with knee flexed, some Permits flexion and extension and, with knee flexed, some internal and external rotationinternal and external rotation



• Ankle joint (Figure 9-12)Ankle joint (Figure 9-12)

Hinge type of synovial jointHinge type of synovial joint

Articulation between lower ends of tibia and fibula Articulation between lower ends of tibia and fibula and upper part of talusand upper part of talus

Joint is “mortise” or wedge-shapedJoint is “mortise” or wedge-shaped

• Lateral malleolus lower than medialLateral malleolus lower than medial



• Ankle joint (cont.)Ankle joint (cont.)

Internal rotation injury results in common “sprained Internal rotation injury results in common “sprained ankle” ankle”

• Involves anterior talofibular ligamentInvolves anterior talofibular ligament

Other ankle ligaments may also be involved in Other ankle ligaments may also be involved in sprain injuries—example is deltoid ligamentsprain injuries—example is deltoid ligament



• Ankle joint (cont.)Ankle joint (cont.)

External ankle rotation injuries generally involve External ankle rotation injuries generally involve bone fractures rather than ligament tearsbone fractures rather than ligament tears

• First-degree ankle injury—lateral malleolus fracturedFirst-degree ankle injury—lateral malleolus fractured

• Second-degree ankle injury—both malleoli fracturedSecond-degree ankle injury—both malleoli fractured

• Third-degree ankle injury—fracture of both malleoli Third-degree ankle injury—fracture of both malleoli and articular surface of tibiaand articular surface of tibia



• Vertebral joints (Figures 9-13 and 9-14)Vertebral joints (Figures 9-13 and 9-14) Vertebrae are connected to one another by Vertebrae are connected to one another by

several joints to form a strong, flexible columnseveral joints to form a strong, flexible column

Bodies of adjacent vertebrae are connected by Bodies of adjacent vertebrae are connected by intervertebral disks and ligamentsintervertebral disks and ligaments

Intervertebral disks are made up of two parts:Intervertebral disks are made up of two parts:

• Annulus fibrosus—disk’s outer rim, made of fibrous Annulus fibrosus—disk’s outer rim, made of fibrous tissue and fibrocartilagetissue and fibrocartilage

• Nucleus pulposus—disk’s central core, made of a pulpy, Nucleus pulposus—disk’s central core, made of a pulpy, elastic substanceelastic substance


Types and Range of Movement Types and Range of Movement at Synovial Jointsat Synovial Joints

• Measuring range of motion (Figure 9-14)Measuring range of motion (Figure 9-14)

Range of motion (ROM) assessment used to Range of motion (ROM) assessment used to determine extent of joint injurydetermine extent of joint injury

ROM can be measured actively or passively; ROM can be measured actively or passively; results of both methods generally about equalresults of both methods generally about equal

ROM measured by instrument called a goniometerROM measured by instrument called a goniometer



• Angular movements—change the size of the Angular movements—change the size of the angle between articulating bonesangle between articulating bones

Flexion—decreases the angle between bones; Flexion—decreases the angle between bones; bends or folds one part on another (Figures 9-15, bends or folds one part on another (Figures 9-15, A, 9-17, and 9-18)A, 9-17, and 9-18)

Extension and hyperextension (Figure 9-17)Extension and hyperextension (Figure 9-17)

• Extension—increases the angle between bones, returns Extension—increases the angle between bones, returns a part from its flexed position to its anatomical positiona part from its flexed position to its anatomical position

• Hyperextension—stretching or extending part beyond its Hyperextension—stretching or extending part beyond its anatomical position (Figures 9-18, 9-20, and 9-22)anatomical position (Figures 9-18, 9-20, and 9-22)



• Angular movements (cont.) Angular movements (cont.) Plantar flexion and dorsiflexion (Figure 9-24)Plantar flexion and dorsiflexion (Figure 9-24)

• Plantar flexion—increases angle between top of foot Plantar flexion—increases angle between top of foot and front of legand front of leg

• Dorsiflexion—decreases angle between top of foot and Dorsiflexion—decreases angle between top of foot and front of legfront of leg

Abduction and adduction (Figures 9-18 and 9-22)Abduction and adduction (Figures 9-18 and 9-22)

• Abduction—moves a part away from median plane Abduction—moves a part away from median plane of bodyof body

• Adduction—moves a part toward median plane of bodyAdduction—moves a part toward median plane of body



• Circular movementsCircular movements

Rotation and circumductionRotation and circumduction

• Rotation—pivoting a bone on its own axis Rotation—pivoting a bone on its own axis (Figure 9-15, D)(Figure 9-15, D)

• Circumduction—moves a part so that its distal Circumduction—moves a part so that its distal end moves in a circleend moves in a circle

Supination and pronation (Figure 9-19, B)Supination and pronation (Figure 9-19, B)

• Supination—turns the hand palm side–upSupination—turns the hand palm side–up

• Pronation—turns the hand palm side–downPronation—turns the hand palm side–down



• Gliding movements—simplest of all Gliding movements—simplest of all movements; articular surface of one bone movements; articular surface of one bone moves over articular surface of another moves over articular surface of another without any angular or circular movementwithout any angular or circular movement



• Special movementsSpecial movements Inversion and eversion (Figure 9-24, B)Inversion and eversion (Figure 9-24, B)

• Inversion—turning sole of foot inwardInversion—turning sole of foot inward

• Eversion—turning sole of foot outwardEversion—turning sole of foot outward

Protraction and retraction (Figure 9-16, B)Protraction and retraction (Figure 9-16, B)

• Protraction—moves a part forwardProtraction—moves a part forward

• Retraction—moves a part backwardRetraction—moves a part backward

Elevation and depressionElevation and depression

• Elevation—moves a part upElevation—moves a part up

• Depression—lowers a partDepression—lowers a part


Cycle of Life: ArticulationsCycle of Life: Articulations

• Bone development and the sequence of ossification Bone development and the sequence of ossification between birth and skeletal maturity affect jointsbetween birth and skeletal maturity affect joints Fontanels between cranial bones disappearFontanels between cranial bones disappear Epiphysial plates ossify at maturityEpiphysial plates ossify at maturity

• Older adultsOlder adults ROM decreasesROM decreases Changes in gait occurChanges in gait occur

• Skeletal diseases manifest as joint problemsSkeletal diseases manifest as joint problems Abnormal bone growth (lipping)—influences joint motionAbnormal bone growth (lipping)—influences joint motion Disease conditions can be associated with specific Disease conditions can be associated with specific

developmental periodsdevelopmental periods


The Big Picture: ArticulationsThe Big Picture: Articulations

• Hand—“reason for the upper extremity” Hand—“reason for the upper extremity” and thumb—“reason for the hand”and thumb—“reason for the hand”

Examples of “Big Picture” type of thinking when Examples of “Big Picture” type of thinking when used in functional contextused in functional context


The Big Picture: ArticulationsThe Big Picture: Articulations

• Mobility of the upper extremity is extensive because Mobility of the upper extremity is extensive because of the following:of the following: Arrangement of bones in shoulder girdle, arms, forearm, Arrangement of bones in shoulder girdle, arms, forearm,

wrist, and handwrist, and hand

Location and method of attachment of muscles to bonesLocation and method of attachment of muscles to bones

Proper functioning of jointsProper functioning of joints

• Mobility and extensive ROM needed to position upper Mobility and extensive ROM needed to position upper extremity and hand to permit grasping and extremity and hand to permit grasping and manipulation of objects, thus enabling effective manipulation of objects, thus enabling effective interaction with objects in external environmentinteraction with objects in external environment

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Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 1 Chapter 9 Articulations