Articulations!! (the Joints) - PowerPoint Presentation

Articulations!! (the Joints)

Section 1: Joint Design and Movement Articulations (_____________________) Where two bones interconnectBones are relatively inflexible so necessary to allow movementReflect compromise between need for strength versus need for ______________________Anatomical structure of each joint determines type and amount of movement possibleCategories from range of motion and subgroups from anatomical structure

Joint types No Movement Have we seen this before? Limited MovementCan you think of any?Free MovementExamples?

Joint Design and Movement Three functional categories _______________________ (no movement)Amphiarthrosis (little movement)____________________________ (free movement)Synarthrotic and amphiarthrotic joints Relatively simple structure Direct connections between bonesDiarthrotic jointsComplex in structurePermit greatest range of motion

Synovial joints Components of synovial joints ___________________ cartilages Resemble hyaline cartilagesMatrix contains more water comparativelyHave no perichondriumSlick and smooth, so reduce frictionAre separated by thin film of synovial fluid Articular Cartilage

Components of synovial joints (continued) ______________ fluid Similar in texture to egg whites Produced at the synovial membraneCirculates from areolar tissue to joint cavityPercolates through articular cartilagesTotal quantity is less than 3 mL Synovial fluid

Components of synovial joints (continued) _________________ capsule Dense and fibrous May be reinforced with accessory structures (tendons and ligaments)Continuous with periosteum of each bone Joint capsule

Functions of synovial fluid Lubrication With articular cartilage compression, synovial fluid is squeezed out and reduces friction between moving surfaces _______________________________ distributionProvide nutrients and oxygen, as well as waste disposal for the chondrocytes of articular cartilagesCompression and reexpansion of articular cartilages pump synovial fluid in and out of cartilage matrix________________________ absorption Distributes compression forces across articular surfaces and outward to joint capsule

Joint Accessory ____________________ (a pouch) Small pocket filled with synovial fluidOften form in areas where tendon or ligament rubs against other tissuesReduce friction and act as shock absorbers Bursa

Accessory structures in knee (continued) Fat pads Adipose tissue covered by synovial membrane Protect articular cartilagesAct as packing material for joint_____________________ (a crescent)Pad of fibrous cartilage between bones of synovial jointMay subdivide joint cavity and affect fluid flow or allow variations in shapes of articular surfaces Meniscus Fat pad

Accessory structures in knee Tendons of quadriceps Pass across joint Limit movementProvide mechanical supportAccessory ligaments__________________, strengthen, and reinforce jointIntrinsic ligamentsLocalized thickening of joint capsuleExample: cruciate liagments of knee ___________________ ligaments Separate from joint capsule May pass inside ( intracapsular ) or outside (extracapsular) the joint capsuleIntracapsular example: cruciate ligaments Extracapsular example: patellar ligament

Synovial joints _________________ vs. strength in jointsGreater range of motion = ______________ jointExamples:Synarthrosis (strongest type of joint, no movement)Diarthrosis (far weaker but broad range of motion)_____________________________ (luxation ) Movement beyond normal range of motion Articulating surfaces forced out of position Can damage joint structures No pain from inside joint but from nerves or surrounding structures

Types of motion and structural types of synovial joints _____________________ Movement along two axes in one plane Angular motionMovement along two axes in one plane with additional change in angle______________________ Special complex angular movement Proximal end of bone remains fixed while distal end can move in a circle (“trace circumference”) Rotation Bone ends remain fixed and shaft rotates

Figure 8.2 6 Gliding joint Hinge joint Pivot joint Ellipsoid joint Saddle joint Ball-and-socket joint The anatomical types of synovial joints, with joint models and examples Types of Synovial Joints Models of Joint Motion Examples Manubrium Clavicle Ulna Humerus Atlas Axis Scaphoid bone Ulna Radius Metacarpal bone of thumb Trapezium Scapula Humerus • Acromioclavicular and claviculosternal joints • Intercarpal and intertarsal joints • Vertebrocostal joints • Sacro-iliac joints • Elbow joints • Knee joints • Ankle joints • Interphalangeal joints • Atlas/axis • Proximal radio-ulnar joints • Radiocarpal joints • Metacarpophalangeal joints 2–5 • Metatarsophalangeal joints • First carpometacarpal joints • Shoulder joints • Hip joints

Flexion and extension Usually applied to movements of long bones of limbs but also axial skeleton ______________________ Anterior/posterior movement that reduces angle between articulating elementsLateral flexionVertebral column bending to the sideDorsiflexion Flexion at ankle joint and elevation of sole ___________________ flexion ( planta , sole)Extension at ankle joint and elevation of heel

Extension Anterior/posterior movement that increases angle between articulating elements__________________Extension past anatomical position

Abduction and Adduction Always refers to movements of appendicular skeleton, not axial Movements are usually toward or away from body midline For fingers or toes, movements are spreading digits apart or bringing them together____________________ (ab, from)Movement away from body longitudinal axis in frontal plane ____________________ ( ad, to) Movement toward body longitudinal axis in frontal plane

Circumduction Moving arm or thigh as if to draw a big _________________ at distal end of limb Wrist Arm

Rotation When applied to the trunk, described as left and right _____________________When applied to limbsMedial rotation (internal or inward rotation)Anterior surface of limb toward trunk long axisLateral rotation (external or outward rotation)Anterior surface of limb away from trunk long axis

Rotation (continued) Other special terms for rotation of forearm ____________________Proximal end of radius rotates near ulnaDistal end rolls across anterior ulnar surfaceTurns the wrist and hand from palm facing front to palm facing back____________________Opposing movement Palm is turned anteriorly

Special movements _______________________ Movement of thumb toward palm surface or other fingers ProtractionMovement forward in anterior plane___________________Reverse of protractionInversion (in, into + vertere , to turn) Twisting foot motion to turn sole inward________________________ (e, out) Opposing movement to inversion

Figure 8.4 2 Special movements Opposition Eversion Inversion Retraction Protraction Depression Elevation

Articulations ____________________skeleton articulations Typically are strong but very little movement ___________________________ skeleton articulationsTypically have extensive range of motionOften weaker than axial articulations

Figure 8 Section 2 1 Joints of the Axial Skeleton Sutures of the skull Temporomandibular joint (temporal bone and mandible) Atlanto-occipital joint (occipital bone and atlas) and the atlanto-axial joint (C 1 –C 2 ) Joints of the thoracic cage Intervertebral joints The lumbosacral joint, which attaches the last lumbar vertebra to the sacrum The sacrococcygeal and intercoccygeal joints, which structurally resemble simplified intervertebral joints

Figure 8 Section 2 2 Joints of the foot and toes Ankle joint Knee joint Hip joint Joints of the hand and fingers Wrist joint Pubic symphysis Superior and inferior radio-ulnar joints Elbow joint The sacro-iliac joint, which firmly attaches the sacrum of the axial skeleton to the pelvic girdle of the appendicular skeleton Shoulder joint The sternoclavicular joint, the only articulation between the axial skeleton and the pectoral girdle and upper limb Joints of the Appendicular Skeleton

Vertebral articulations Between superior and inferior articular processes of adjacent vertebrae Gliding ______________________________ joints Permit flexion and rotationAdjacent vertebral bodies form symphyseal joints with _______________________________ discsNumerous ligaments attach bodies and processes of vertebrae to stabilize column

Intervertebral discs Composition __________________________ fibrosis Tough outer layer of fibrous cartilageCollagen fibers attach to adjacent vertebrae___________________ pulposusSoft, elastic, gelatinous core Provides resiliency and shock absorption Account for ¼ length of vertebral column Water loss from discs causes shortening of vertebral column with age and increases risk of disc injury

Figure 8.5 2 The ligaments attached to the bodies and processes of all vertebrae Primary Vertebral Ligaments Ligamentum flavum Posterior longitudinal ligament Interspinous ligament Supraspinous ligament Anterior longitudinal ligament Lateral view Sectional view Posterior longitudinal ligament Spinal nerve Spinal cord Anulus fibrosus Nucleus pulposus Intervertebral disc

Primary vertebral ligaments Ligamentum ______________________ Connects adjacent vertebral laminaePosterior longitudinal ligamentConnects posterior surfaces of adjacent vertebral bodiesInterspinous ligamentConnects spinous processes of adjacent vertebrae Supraspinous ligament Connects spinous processes from sacrum to C7 Ligamentum nuchae from C 7 to base of skull _______________________________ longitudinal ligament Connects anterior surfaces of adjacent vertebral bodies

Disorders of vertebral column _______________________ disc Posterior longitudinal ligaments weaken causing more pressure on discs Nucleus pulposus compresses, distorts anulus fibrosusDisc bulges into vertebral canal (doesn’t actually slip)________________________ discNucleus pulposus breaks through anulus fibrosusSpinal nerves are often affected

Disorders of vertebral column (continued) ______________________ ( penia, lacking)Inadequate ossification leading to loss of bone massOften occurs with age beginning between ages 30 and 40More severe in women than menOsteoporosis (porosus, porous)Bone loss sufficient to affect normal function

Figure 8.5 5 The effects of osteoporosis on spongy bone Clinical scan of a compression fracture in a lumbar vertebra

Figure 8.5 5 The effects of osteoporosis on spongy bone Normal spongy bone SEM x 25 SEM x 21 Spongy bone with osteoporosis

Ball and Socket Shoulder joint ( glenohumeral joint)__________________ range of motion of any jointMost frequently dislocated jointDemonstrates stability sacrificed for mobilityMost stability provided by surrounding skeletal muscles, associated tendons, and various ligamentsBall-and-socket diarthrosis Formed by head of humerus and glenoid cavity of scapula

Hip joint Sturdy ball-and-socket joint Although not directly aligned with weight distribution along femur shaft, which can produce fractures of femoral neck or intertrochanteric region Permits _______________, extension, adduction, abduction, circumduction, and rotationFormed by head of femur and acetabulum of hip bone

Figure 8.6 5 Greater trochanter Inter- trochanteric line Lesser trochanter Anterior view The ligaments of the hip joint in anterior view The ligaments of the hip joint in posterior view Posterior view Ischial tuberosity Pubofemoral ligament Iliofemoral ligament Ischiofemoral ligament Reinforcing Ligaments The ligaments of the hip joint

Hinge Elbow joint Complex __________________ joint involving humerus, radius, and ulna Extremely strong and stable due to: Bony surfaces of humerus and ulna interlock Single, thick articular capsule surrounds both humero-ulnar and proximal radio-ulnar joints Articular capsule reinforced by strong ligaments Severe stresses can still produce dislocations or other injuries Example: ___________________ elbow Muscles flexing elbow attach on anterior while those extending attach on the posterior

Figure 8.7 1 The elbow joint Humeroulnar joint Posterior view Olecranon fossa Olecranon Ulna Humerus

Elbow and knee joints Elbow joint (continued)Specific joints of the elbow_____________________jointCapitulum of humerus articulating with head of radiusHumero-ulnar jointLargest and strongest articulationTrochlea of humerus articulates with trochlear notch of ulna Shape of ulnar notch determines plane of movement Shapes of olecranon fossa and olecranon limit degree of extension Proximal radio-ulnar joint is ___________part of elbow joint

Elbow and knee joints Elbow joint (continued) Reinforcing ligamentsRadial _________________ ligamentStabilizes lateral surface of jointUlnar collateral ligamentStabilizes medial surface of joint____________________ ligamentBinds head of radius to ulna

Elbow and knee joints Knee joint Contains _____________separate articulationsMedial condyle of tibia to medial condyle of femurLateral condyle of tibia to lateral condyle of femurPatella and patellar surface of femurPermits flexion, extension, and very limited _______________

Elbow and knee joints Knee joint (continued)External supportQuadriceps tendon to patellaContinues as patellar ligament to anterior tibiaFibular collateral ligamentLateral support Tibial collateral ligament Medial support _________________________ligaments Posterior support extending between femur and heads of tibia and fibulaTendons of several muscles that attach to femur and tibia

Elbow and knee joints Knee joint (continued)Internal support___________________ ligaments limit anterior/posterior movement of femur and maintain alignment of condylesAnterior cruciate ligament (ACL)At full extension, knee becomes “locked” (slight lateral rotation tightens ACL, and lateral meniscus forced between tibia and femur) Opposite motion to “unlock” Posterior cruciate ligament (PCL)

Elbow and knee joints Knee joint (continued)Internal support (continued)Medial and lateral _______________Fibrous cartilage pads between tibial and femoral condylesAct as cushions and provide lateral stability to joint

Disruption to normal joint function Arthritis Damage to articular cartilages but specific cause variesExposed surfaces change from slick, smooth-gliding to rough feltwork of collagen fibers increasing frictionRheumatism (pain and stiffness affecting the skeletal and/or muscular systems) is often a symptomOsteoarthritis Also known as degenerative arthritis or degenerative joint disease Generally affects individuals age 60 and older25% of women, 15% of menCan result from cumulative wear and tear of joints or genetic factors affecting collagen formation

Figure 8.8 1 – 2 Comparisons of normal articular cartilage with articular cartilage damaged by osteoarthritis Normal Joint Arthritic Joint Articular cartilage LM x 180 Fibrous remains of the articular cartilage Degenerating articular cartilage LM x 180 Arthroscopic view of normal cartilage Arthroscopic view of damaged cartilage

Disruption to normal joint function Visualizing problematic joints Arthroscopic surgeryOptical fibers (arthroscope) inserted into joint through small incision without major surgery to visualize joint interiorIf necessary, other instruments can be inserted through other incisions to permit surgery within view of arthroscope_____________________ resonance imaging Cost-effective and noninvasive viewing technique that allows examination of soft tissues around joint as well

Figure 8.8 3 An arthroscopic view of the interior of the left knee, showing injuries to the anterior and posterior cruciate ligaments. PCL ACL Femoral condyle Meniscus

Figure 8.8 4

Disruption to normal joint function _____________________ jointsMay be last resort if other solutions (exercise, physical therapy, drugs) for joint problems failNot as strong as natural joints, so most suitable for elderlyTypically have service life of about 10 years

Figure 8.8 5

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