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Essentials of Human Anatomy & Physiology Elaine N. Marieb Seventh Edition Articulations aka. Joints Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fundamental Functions Hold bones together Allow for mobility Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.43 Classification of Joints Overall classification is based on 3 criteria: Highlight these in your notes Amount of motion allowed Type of material that binds bones together Presence or absence of joint capsule Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.43 Classification Functionally – based on amount of motion allowed Synarthroses, amphiarthroses, diarthroses Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.43 Functional Classification of Joints Synarthroses – immovable joints Amphiarthroses – slightly moveable joints Diarthroses – freely moveable joints Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.44 Where in the Body? Diarthroses found in limbs where mobility is important Synarthroses and amphiarthroses are found in the axial skeleton where security/strength and protection of organs is important Structural Classification of Joints Structural – based on type of material that binds joint together and on presence/absence of joint capsule Fibrous Cartilaginous Synovial Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.44 Structural Classification of Joints Fibrous joints (Synarthroses) Generally immovable - Synarthrotic No joint capsule Joined by fibrous connective tissue Examples: Sutures Syndesmoses Gomphoses Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.45 Sutures Occur between bones of the skull Edges of bone interlock and fuse Syndesmoses Connected by ligament or interosseous membrane (longer connecting fibers = a little more “give”) Examples: Distal tibiofibular joint Down the length of the radius and ulna Gomphoses Tooth held by the periodontal ligament into the mandible/maxilla socket Cartilaginous Joints (Amphiathroses) Immovable or slightly moveable Joined by cartilage No joint capsule Examples: A. Symphyses B. Synchondroses Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.45 Symphyses Pad or plate of FIBROcartilage – slightly movable Examples Pubic symphysis Intervertebral joints Sternal angle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.27b, c Slide 5.47 Synchondroses Connected by bar or plate of HYALINE cartilage Examples: Epiphyseal plate Costal cartilages to ribs Synovial Joints (Diarthroses) Freely moveable Articulating bone ends are separated by a joint cavity completely filled with synovial fluid Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.45 Synovial Joint Structure Articular cartilage (hyaline cartilage) covers the ends of bones to cushion & protect Joint surfaces are enclosed by a double layered articular capsule (joint capsule) Fibrous capsule – outer capsule – continuous with periosteum Synovial membrane – inner lining – continuous with articular cartilage. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.49 Synovial Joint Structure Synovial membrane – secretes synovial fluid into the joint cavity Synovial fluid lubricates the joint surfaces to reduce friction. It also nourishes the articular cartilage through diffusion of substances Ligaments reinforce the joint Intracapsular, extracapsular, capsular Sports Application Synovial fluid becomes less viscous (thick) when it is warm. This allows the joint to move more freely. Just another reason to warm up before you stretch and do other activities. Just like the oil in your car needs to warm up so it can lubricate the car parts! Structures Associated with the Synovial Joint Bursae – flattened fibrous sacs lined with synovial membrane and filled with synovial fluid Located where ligaments, muscle, skin, tendons and bone rub together to reduce friction (knee & elbow) False (develop at areas of high friction) vs true (born with) Tendon sheath Elongated bursa that wraps around a tendon Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.50 Inflammatory Conditions Bursitis – inflammation of a bursa usually caused by a blow or friction caused by excessive & repetitive exercise. Tendonitis – inflammation of tendon sheaths Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.53 Synovial Joint Structure Miscellaneous structures Fatty pads – located between fibrous capsule & synovial membrane or bone Menisci – Fibrocartilage pads – subdivide cavity and improve stability/fit The Synovial Joint sp-Joints.url Figure 5.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.51 Types of Synovial Joints Based on Shape Figure 5.29a–c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide Types of Synovial Joints Based on Shape sp-Joints.url Figure 5.29d–f Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide Examples of Synovial Joints Non axial – aka plane – gliding motion Examples: intercarpal, intertarsal Uniaxial – one plane of motion Hinge: elbow, knee, interphalangeal, talus with tibia Pivot: atlantoaxial, proximal radioulnar Examples of Synovial Joints Biaxial – two planes of motion Condyloid: metacarpophalangeal, atlantooccipital, radiocarpal Saddle: carpometacarpal joints of thumbs only Examples of Synovial Joints Multiaxial – universal motion Ball & socket: hip, shoulder Synovial Joint Movements Movements Get together in groups Define each motion in words – starting on p.268 Act out each motion Create a “Cheer” that uses the motions & their names to help you remember them. Stability of Joints Articular surfaces: shallow vs. deep Muscle tone is the MAJOR factor that determine joint stability. Bigger muscles = bigger tendons = bigger bone attachment points (Wolff’s law) Ligaments: more ligaments = equal more stability (also the amount of stress on the ligament) Shoulder Joint Shoulder Joint Most freely movable but most least stable Ball & socket joint Glenoid labrum: rim of fibrocartilage that deepens glenoid cavity Reinforcing ligaments primarily on anterior aspect Muscle tendons are most important in stabilty Shoulder Joint Superstabilizer of joint is the tendon of the long head of the biceps brachii muscle Shoulder Joint Rotator cuff Other fused tendons for stability Can be stretched & injured during vigorous circumduction Shoulder Joint Dislocates inferiorly/anteriorly due to weakness of reinforcements Elbow Joint Very stable hinge joint Main portion of joint is trochlea with semilunar notch Elbow Joint 3 important ligaments Medial collateral Lateral collateral Annular ligament – encloses the radial head for stability during pronation & supination Several tendons cross joint to provide stability Ligaments of Elbow Hip Joint Less movable but very stable Large muscles & ligaments Deep socket Acetabular labrum enhances depth of socket Hip displacements are rare due to the stability of the joint – It takes great force to dislocate a hip joint Hip Joint Hip Socket 3 main ligaments Iliofemoral Pubofemoral ischiofemoral Hip Joint These ligaments are arranged so that the head of the femur is actually screwed deeper into the socket upon standing Ligamentum teres contains a small artery that supplies nutrients to the head of the femur. Any damage to this artery can lead to severe arthritis Hip Joint This is the most common joint replaced. The Knee Knee Joint Structure Largest joint in body - Very complex Joint is only partially enclosed by capsule – capsule is absent anteriorly – This increases the flexibility of the knee Contains 10 bursae (& maybe additional false bursa) Knee Bursae Menisci C-shaped fibrocartilage – deepen articular cartilage Menisci Increases lateral stability Absorbs shock Only attached at outer margin so loose ends are frequently torn in sports injuries Reinforcement Extracapsular – help stabilize entire joint Patellar ligament Lateral collateral – critical in preventing lateral angular motion Medial collateral – critical in preventing medial angular motion Oblique popliteal Arcuate popliteal Intracapsular Help prevent displacement of articular surfaces Anterior cruciate Attached to the anterior tibia Prevents overextension Taut when knee is extended Posterior cruciate Attached to the posterior tibia Prevents overflexion Taut when knee is flexed Stability The knee is strongly reinforced by muscles, tendons, and ligaments BUT relatively unprotected by muscle Muscle strength is very important for stability – bigger muscles = bigger tendons that help to stabilize Muscles Anterior Knee Structure Structures Most Often Injured Medial Meniscus Medial Collateral Ligament Anterior Cruciate Ligament This ligament is tight (taut) when the joint is extended The posterior ligament is tight when the joint is flexed – so it is harder to injure Homeostatic Imbalances Sprains Stretched & torns ligaments Heal slowly due to poor vascularity of cartilage Dislocations or Subluxation must be reduced Arthritis Main definition: synovial membrane thickening and decrease in synovial fluid production Osteoarthritis Define: Chronic Degenerative (non inflammatory) Who affected: aged Symptoms: Erosion of articular cartilages, contact of bone surfaces, bone spurs form that enlarge the bone ends, joint motion restricted, stiffness & pain Osteoarthritis Major symptom: crepitus: crunching noise made by affected joints resulting from contact of roughened articular surfaces Treatment: analgesics, bedrest, moderate exercise Ostearthritis Rheumatoid Arthritis Define: autoimmune disorder, chronic inflammatory Who affected: women age 40+ (also a juvenile version) Symptoms: bilateral, remissions & exacerbations, synovial membrane thickens & fluid production decreases, cartilage & bone may eventually be eroded away Rheumatoid Arthritis Pannus: abnormal tissue that clings to articular cartilage – may cause joint fusion known as ANKYLOSIS Treatments: drug therapy, cold & hot packs, mild exercise to prevent fusion, joint replacement Rheumatoid arthritis Rheumatoid Arthritis Gouty Arthritis Define: Hyperurecemia – buildup of sodium urate crystals Most commonly affected: men Symptoms: usually single joint – swollen & painful Treatments: drug therapy if continual, cold pack & analgesics, watch diet (liver, kidney, sardines, anything high in purines), avoid alcohol and excessive Vitamin C Gouty Arthritis Gout Extra Terms Ankylosing Spondylitis: variation of rheumatoid arthritis – affects men – progresses superiorly along spine causing spinal fusion Synovitis: inflammation of synovial membrane of a joint causing swelling & joint movement limitation