JOINTS/ARTICULATIONS - Jackson County Faculty … · JOINTS/ARTICULATIONS ... Adduction – moving...

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JOINTS/ARTICULATIONS The sites where two or more bones meet are called joints. Joints have 2 fundamental functions gives our skeleton mobility and holds it together. Joints are classified by structure and function. Functional classification is based on amount of movement allowed at the joint --- Synarthroses (immovable joints), Amphiarthroses (slightly movable joints), Diarthroses (freely movable joints) Structural classification focuses on material binding the bones together and presence or absence of a joint cavity --- Fibrous joints, Cartilaginous joints, Synovial joints. 1. Fibrous Joints bones joined by dense fibrous connective tissue; no joint cavity. Most are synarthrotic (immovable). 3 types Sutures (rigid, interlocking joints), Syndesmoses (bones connected by ligaments), Gomphoses (peg-in-socket joint of teeth) 2. Cartilaginous Joints bones are united by cartilage; no joint cavity; not highly moveable. 2 types Synchondroses (plates of hyaline cartilage unites bone all are synarthrotic), Sympheses (fibrocartilage unites bone flexible amphiarthroses) 3. Synovial Joints bones are separated by a fluid-filled joint cavity; all are diarthrotic. Includes all limb joints and most joints of body. Distinguishing features of synovial joints articular cartilage, synovial cavity, articular capsule, synovial fluid, reinforcing ligaments, nerves, blood vessels. Other features of Synovial joints: Fatty pads - For cushioning between fibrous layer and synovial membrane or bone Articular discs (menisci) - Fibrocartilage separates articular surfaces to improve "fit" of bone ends, stabilize joint, and reduce wear and tear Bursae - Sacs lined with synovial membrane; contains synovial fluid; Reduce friction where ligaments, muscles, skin, tendons, or bones rub together Tendon Sheaths - Elongated bursa wrapped completely around tendon subjected to friction Stabilizing Factors of Synovial joints: Shapes of articular surfaces Ligament number and location Muscle tendons that keep joint taunt muscle tone keeps tendons taut Range of motion: Nonaxialslipping movements only Uniaxialmovement in one plane Biaxialmovement in two planes Multiaxialmovement in or around all three plane

Transcript of JOINTS/ARTICULATIONS - Jackson County Faculty … · JOINTS/ARTICULATIONS ... Adduction – moving...

JOINTS/ARTICULATIONS The sites where two or more bones meet are called joints. Joints have 2 fundamental functions – gives our skeleton mobility and holds it together. Joints are classified by structure and function. Functional classification is based on amount of movement allowed at the joint --- Synarthroses (immovable joints), Amphiarthroses (slightly movable joints), Diarthroses (freely movable joints) Structural classification focuses on material binding the bones together and presence or absence of a joint cavity --- Fibrous joints, Cartilaginous joints, Synovial joints. 1. Fibrous Joints – bones joined by dense fibrous connective tissue; no joint cavity. Most are

synarthrotic (immovable). 3 types – Sutures (rigid, interlocking joints), Syndesmoses (bones connected by ligaments), Gomphoses (peg-in-socket joint of teeth)

2. Cartilaginous Joints – bones are united by cartilage; no joint cavity; not highly moveable. 2 types – Synchondroses (plates of hyaline cartilage unites bone – all are synarthrotic), Sympheses (fibrocartilage unites bone – flexible amphiarthroses)

3. Synovial Joints – bones are separated by a fluid-filled joint cavity; all are diarthrotic. Includes all limb joints and most joints of body. Distinguishing features of synovial joints – articular cartilage, synovial cavity, articular capsule, synovial fluid, reinforcing ligaments, nerves, blood vessels.

Other features of Synovial joints: Fatty pads - For cushioning between fibrous layer

and synovial membrane or bone Articular discs (menisci) - Fibrocartilage separates

articular surfaces to improve "fit" of bone ends, stabilize joint, and reduce wear and tear

Bursae - Sacs lined with synovial membrane; contains synovial fluid; Reduce friction where ligaments, muscles, skin, tendons, or bones rub together

Tendon Sheaths - Elongated bursa wrapped completely around tendon subjected to friction

Stabilizing Factors of Synovial joints: • Shapes of articular surfaces • Ligament number and location • Muscle tendons that keep joint taunt – muscle tone keeps tendons taut Range of motion: • Nonaxial—slipping movements only • Uniaxial—movement in one plane • Biaxial—movement in two planes • Multiaxial—movement in or around all three plane

Synovial Joints – movements allowed: All muscles attach to bone or connective tissue at no fewer than two points. Origin—

attachment to immovable bone. Insertion—attachment to movable bone Muscle contraction causes insertion to move toward origin. Movements occur along transverse, frontal, or sagittal planes. Angular Movements:

Flexion - movement that decrease angle of joint and brings 2 bones closer together

Extension – movement that increases angle of joint; Hyperextension – extension >180o

Abduction – moving a limb away from the midline of the body

Adduction – moving a limb toward the midline of the body

Rotation – movement of a bone around its longitudinal axis

Circumduction – combination of flexion, extension, abduction, adduction

Dorsiflexion – standing on your heels

Plantar flexion – standing on your toes

Inversion – turning sole medially

Eversion – turning the sole laterally

Supination – forearm rotates laterally so that the palm faces anterior

Pronation - forearm rotates medially so the palm faces posterior

Types of Synovial Joints – based on shape of articular surfaces.

Planes, hinge, pivot, condylar, saddle, ball-and-socket

Knee Joint – Capsules are reinforced by muscle tendons.

Anteriorly, quadriceps tendon gives rise to three broad ligaments - - - Medial and lateral patellar retinacula, Patellar ligament

Ligaments stabilize joint Capsular and extracapsular ligaments:

Fibular and tibial collateral ligaments,

Oblique popliteal ligament, Arcuate popliteal ligament

Intracapsular ligaments: Anterior cruciate ligament (attaches to anterior tibia), Posterior cruciate ligament (attaches to posterior tibia) ---prevent anterior-posterior displacement

Knee joint injuries - absorbs great vertical force; vulnerable to horizontal blows, especially lateral blows to extended knee --- Collateral ligaments, Cruciate ligaments, Cartilages

Shoulder Joint –

Reinforcing ligaments are primarily on anterior aspect -- Coracohumeral ligament (helps support weight of upper limb), Three glenohumeral ligaments

Reinforcing muscle tendons; tendon of long head of biceps brachii – secures humerus to glenoid cavity; 4 rotator cuff tendons encircle shoulder joint : Subscapularis, Supraspinatus, Infraspinatus, Teres minor

Coxal Joint –

Head of femur articulates with acetabulum – good range of motion, but limited by deep socket. Rim of fibrocartilage – acetabular labrum enhances depth of socket so hit dislocations rare.

Reinforcing ligaments - Iliofemoral ligament, Pubofemoral ligament, Ischiofemoral ligament, Ligamentum teres

Common Joint Injuries: Cartilage tears – due to compression and shear stress; fragments may cause joint to lock or

bind. Cartilage rarely repairs itself – repaired with arthroscopic surgery. Ligaments repaired, cartilage fragments removed with minimal tissue damage or scarring. Partial menisci removal renders joint less stable, but still mobile --- complete removal leads to osteoarthritis. Meniscal transplant in younger patients.

Sprains – reinforcing ligaments stretched or torn; partial tears slowly repair and heal; poor vascularization. 3 options if torn completely – ends sewn together, replaced with grafts, time and immobilization.

Dislocations (luxations) – bones are forced out of alignment; accompanied by sprains, inflammation and difficulty moving joints -- must be reduced to treat.

Subluxation – partial dislocation of a joint. Bursitis – inflammation of bursa, usually caused by a blow or friction. Treated with rest, ice and

anti-inflammatory drugs. Tendonitis – inflammation of tendon sheaths typically caused by overuse. Symptoms and

treatment similar to bursitis. Arthritis – different types of inflammatory or degenerative diseases that damage joints.

Symptoms include pain, stiffness and swelling of joints. Acute forms – caused by bacteria and treated with antibiotics. Chronic forms – osteoarthritis, rheumatoid arthritis and gouty arthritis.

Osteoarthritis – common, irreversible and degenerative arthritis; may reflect excessive release of enzymes that break down articular cartilage. More cartilage is destroyed than replaced in badly aligned or overworked joints; exposed ends thicken, enlarge, form bone spurs and restrict movement. Treatment – moderate activity, mild pain relievers, capsaicin creams. By age of 85, ½ of Americans develop OA – more women than men.

Rheumatoid Arthritis – chronic, inflammatory, autoimmune disease of unknown cause. Usually arises between 40-50 years – affects 3 times as many women as men. Symptoms include – joint pain, swelling, anemia, osteoporosis, muscle weakness, cardiovascular problems. Anti-inflammatory drugs decrease pain and inflammation – immune suppressants slow the autoimmune reaction; can replace joint with prosthesis.

Gouty Arthritis – deposition of uric acid crystals in joints and soft tissues, followed by inflammation --- more common in men. Typically affects joints at base of great toe – if untreated, bone ends fuse and immobilize joint. Treatment includes drugs, plenty of water and avoidance of alcohol.

Developmental Aspects of Joints: By embryonic week 8, synovial joints resemble adult joints Joint's size, shape, and flexibility modified by use Advancing years take toll on joints --- ligaments and tendons shorten and weaken;

intervertebral discs more likely to herniate; most people in 70s have some degree of OA Full-range-of-motion exercise key to postponing joint problems