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Chapter 8Joints of the Skeletal System Articulations Junctions between bones Bind parts of skeletal system together Make bone growth possible Permit parts of the skeleton to change shape duringchildbirth Enable body to move in response to skeletal musclecontraction

Joints ArticulationsArticulation – site where two or more bonesmeetTwo Fundamental Functions of Joints:Allow the skeleton to have mobilityHold the skeleton together

Joints – Structural and Functional ClassesThree Structural Classifications: Fibrous – suture, syndesomosis, gomphosis Cartilaginous – synchondrosis, symphysis SynovialThree Functional Classifications Synarthrosis – immovable Amphiarthrosis – slightly movable Diarthrosis – freely movable

Classification of Joints Fibrous Joints dense connective tissues connectbones between bones in close contact Cartilaginous Joints hyaline cartilage or fibrocartilageconnect bones Synovial Joints most complex allow free movement synarthrotic immovable amphiarthrotic slightly movable diarthrotic freely movable

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Fibrous Joints3 Types Syndesmosis Suture GomphosisSyndesmosis long fibers connectbones amphiarthrotic distal ends of tibiaand fibula

Fibrous JointsSuture between flat bones synarthrotic thin layer of connectivetissue connects bonesGomphosis cone-shaped bonyprocess in a socket tooth in jawbone synarthrotic

Cartilaginous Joints2 Types Synchondrosis SymphysisSynchondrosis bands of hyaline cartilageunite bones epiphyseal plate(temporary) between manubrium andfirst rib synarthrotic

Cartilaginous JointsSymphysis pad of fibrocartilage between bones pubis symphysis joint between bodies of vertebrae amphiarthrotic

Synovial Joints diarthrotic joint cavity synovial fluid joint capsule synovial membrane bursae

Types of Synovial JointsBall-and-Socket Joint hip shoulderCondyloid Joint between metacarpalsand phalanges

Types of Synovial JointsGliding Joint between carpals between tarsalsHinge Joint elbow between phalanges

Types of Synovial JointsPivot Joint between proximalends of radius andulnaSaddle Joint between carpal andmetacarpal of thumb

Angular Movement – Changeof Angle Between BonesFlexion — bending movement that decreases theangle of the jointExtension — reverse of flexion; joint angle increasesDorsiflexion and Plantar flexion — up and downmovement of the footAbduction — movement of a limb away from themidline or median planeAdduction — movement of a limb toward the midlineor median planeCircumduction — movement of a limb describing acone in space

Types of Joint Movements abduction/adduction dorsiflexion/plantarflexion flexion/extension/hyperextension

RotationThe turning of a bone around its own long axisExamples:Between first two vertebraeHip and shoulder joints

Types of Joint Movements rotation/circumduction supination/pronation

Special MovementsSupination and Pronation – refer to movements ofradius around the ulna (also applied to foot movements)

Types of Joint Movements eversion/inversion protraction/retraction elevation/depression

Special MovementsInversion and EversionProtraction and Retraction

Special MovementsElevation and DepressionOpposition

Shoulder Joint ball-and-socket head of humerus glenoid cavity of scapula loose joint capsule bursae ligaments preventdisplacement very wide range ofmovement

Shoulder Joint

Elbow Joint hinge joint trochlea of humerus trochlear notch of ulna gliding joint capitulum of humerus head of radius flexion and extension many reinforcing ligaments stable joint

Elbow Joint

Hip Joint ball-and-socket joint head of femur acetabulum heavy joint capsule many reinforcing ligaments less freedom of movementthan shoulder joint

Hip Joint

Knee Joint largest joint most complex medial and lateral condyles of distalend of femur medial and lateral condyles ofproximal end of tibia femur articulates anteriorly withpatella modified hinge joint flexion/extension/little rotation strengthened by many ligaments andtendons menisci separate femur and tibia bursae

Knee Joint

Life-Span Changes Joint stiffness is an early sign of aging Regular exercise can prevent stiffness Fibrous joints first to strengthen overa lifetime Changes in symphysis joints ofvertebral column diminish flexibilityand decrease height Synovial joints lose elasticity

Clinical ApplicationJoint DisordersSprains damage to cartilage, ligaments, or tendons associatedwith joints forceful twisting of jointBursitis inflammation of a bursa overuse of a jointArthritis inflamed, swollen, painful joints Rheumatoid Arthritis Osteoarthritis Gout

Joint Injuries – Sprains & Cartilage InjurySprain - the ligaments in a joint are stretched or torn.Partially torn ligaments may repair themselves, buthealing is slow due to lack of vascularization.Completely torn ligaments require surgical repair.Cartilage is mostly avascular and largely unable torepair itself when torn. Most cartilage injuriesinvolve tearing of the menisci.

Dislocations - LuxationOccur when bones are forced out of alignmentUsually accompanied by sprains, inflammation, andjoint immobilizationSubluxation – partial dislocation of a joint

Inflammatory ConditionsBursitisInflammation of a bursa, usually caused by ablow or friction. Symptoms are pain and swelling.Treated with anti-inflammatory drugs; excessivefluid may be aspirated.TendonitisInflammation of tendon sheaths.Symptoms and treatment are similar to bursitis.

Ligament and Cartilage Tears:Example of the Knee Joint

Knee Ligaments and Tendons –Anterior ViewTendon of theQuadriceps FemorisLateral and MedialPatellar RetinaculaFibular and TibialCollateral LigamentsPatellar Ligament

Knee Ligaments and other Supporting StructuresIntracapsular Ligaments (but outside of synovial cavity)Ant.Cruciate LigamentPost. Cruciate LigamentSemilunar CartilagesMedial MeniscusLateral meniscus

Knee Ligaments and other Supporting StructuresAdductor MagnusTendonArticular CapsuleOblique PoplitealLigamentArcuate PoplitealLigamentSemimembranosusTendon

Knee Injury

Arthritis More than 100 different types of inflammatoryor degenerative diseases that damage the joints Most widespread crippling disease in the U.S.(1 out of every 7 people) Symptoms – pain, stiffness, and swelling of ajoint Acute forms are caused by bacteria and aretreated with antibiotics Chronic forms include osteoarthritis,rheumatoid arthritis, and gouty arthritis

Arthritis: Causes and Symptoms

Osteoarthritis (OA) Most common chronic arthritis; often called“wear-and-tear” arthritis Affects women more than men 85% of all Americans develop OA More prevalent in the aged, and is probablyrelated to the normal aging process

Osteoarthritis: Course OA reflects the years of abrasion and compressioncausing increased production of metalloproteinaseenzymes that break down cartilage As one ages, cartilage is destroyed more quickly than itis replaced The exposed bone ends thicken, enlarge, form bonespurs, and restrict movement Crepitus – crunching noise as roughened articularsurfaces rub together Joints most affected are the cervical and lumbar spine,fingers, knuckles, knees, and hips

Osteoarthritis: Treatments OA is usually slow and irreversible Treatments include:– Mild pain relievers, along with moderate activity– Magnetic therapy?– Glucosamine sulfate? said to decrease pain andinflammation

Rheumatoid Arthritis (RA) Chronic, inflammatory, autoimmune disease ofunknown cause, with an insidious onset Usually arises between the ages of 40 to 50, but mayoccur at any age Signs and symptoms include joint tenderness, anemia,osteoporosis, muscle atrophy, and cardiovascularproblems– The course of RA is marked with exacerbationsand remissions

Rheumatoid Arthritis: Course RA begins with synovitis of the affected joint Inflammatory chemicals are inappropriately released Inflammatory blood cells migrate to the joint, causingswelling Inflamed synovial membrane thickens into a pannus Pannus erodes cartilage, scar tissue forms,articulating bone ends fuse The end result, ankylosis, produces bent, deformedfingers

Rheumatoid Arthritis: Treatment Conservative therapy – aspirin, long-term useof antibiotics, and physical therapy Progressive treatment – anti-inflammatorydrugs or immunosuppressants The drug Enbrel, a biological responsemodifier, neutralizes the harmful properties ofinflammatory chemicals

Gouty Arthritis Deposition of uric acid crystals in joints and softtissues, followed by an inflammatory response Typically, gouty arthritis affects the joint at the baseof the great toe In untreated gouty arthritis, the bone ends fuse andimmobilize the joint Treatment – colchicine, nonsteroidal antiinflammatory drugs, and glucocorticoids