Ch. - Articulations PDF

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Summary

Notes from the Articulations unit...

Description

Ch. - Articulations Joints (Articulations) ● ● ●

The weakest part of the skeleton Articulation – the site where two or more bones meet Functions of joints ○ Give the skeleton mobility ○ Hold the skeleton together

Classification of Joints ● Structure - material holding bones together ○ Fibrous- connective tissue ○ Cartilaginous- cartilage ○ Synovial - combo (freely moving joints) ■ Cavity ■ Synovial fluid ●

Function- how much movement it allows (degree of movement ○ Synarthroses -immovable ○ Amphiarthoses- slightly movable ○ Diartheoses - freely movable

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Fibrous ● Bones joined by fibrous tissues ● No joint cavity ● Immovable ● Types ○ Sutures ■ Between bones of the skull ■ Interlocking junctions ○ Syndesmoses ■ Bones connected by fibrous tissue ligaments ■ Examples ● Connection btwn tibia and fibula ○ Gomphoses ■ Peg-in-socket fibrous joint ■ Fibrous connection in the periodontal ligament Cartilaginous ● United by cartilages ● Lack of joint cavity ● Types ○ Syncdocoses ■ No movement ■ Bar or plate of hyaline cartilage unites the bones ■ ○ Symphyses

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A little bit of movement Lots if strength, lots of mobility

Synovial ● Fluid containing joints cavity ● Freely moveable- diarthrosis ● Always have all of the following ○ Articular cartilage ○ Joint (synovial) cavity ○ Articular capsule ○ Synovial Fluid - lubrication ○ Reinforcing ligaments - reinforcement ● Structures

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General Friction-Reducing Structures ■ Bursae- Flattened, fibrous sacs lines with synovial membranes and containing synovial fluid ● Common where ligaments, muscles, skin, tendons, or bones rub together ■ Tendon sheath- elongated bursa that wraps completely around a tendon Stability - determined by

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Articular surfaces - shape determine what movements are possible Ligaments- unite bone and prevent excessive or undesirable motion Muscle tone is accomplished by ● Muscle tendons across joints acting as stabilizing factors ● Tendons that are kept tight at all times by muscle tone ○ Movement ■ Types of muscle attachment across a joint: ● Origin - attachment to the immovable bone ● Insertion- attachment to the movable bone ■ Described as movement along traverse, frontal or sagittal planes ■ Range of motion ● Nonaxial- slipping movements only ○ Bones going over one another ● Uniaxial - movement in one plane ○ One axis (parallel) ● Biaxial- movement in two planes ○ Two directions (perpendicular) ● Multiaxial- movement in or around all three planes ○ All directions ( around the world) ■ Gliding Movement ● One flat bone surface glides or slips over another similar surface ● Ex. intercarpal and intertarsal joints ■ Angular movement ● Flexion - bending movement that decreases the angle on the joint ● Extension- reverse of flexion; joint angle is increased (to 180) ○ Hyperextension (past 180) ● Dorsiflexion - (up) ● Plantar flexion - (point down) ● Abduction - a movement away from the midline ● Adduction - movement towards the midline ● Circumduction - cone-shaped movement ■ Rotational Movement ● Turning a bone around its own long axis ■ Special Movement ● Supination - waiter brings your soup ● Pronation- pro basketball players ● Inversion ● Eversion ● Elevation ● Depression ● Opposition Types of Synovial Joints ○ Plane joints

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Hinge joints Pivot joints Condyloid or Ellipsoidal ■ Biaxial Saddle joints ■ Biaxial ■ Thumb Ball and Socket ■ Multi ■ Shoulder, hip

Knee ● Three joints in one surrounded by a single joint cavity ○ Femoraopatellar ○ Lateral and medial tibiofemoral joints ● Ligaments ○ Lateral and medial ( ○ Fibular and fibular collateral (medial) Shoulder ● Weak stability is maintaunted by ○ Thin, loose joint capsule ○ Four ligaments – coracohumeral, and three glenohumeral ○ Tendon of the long head of biceps, which travels through the intertubercular groove and secures the humerus to the glenoid cavity ○ Rotator cuff (four tendons) that encircles the shoulder joint and blends with the articular capsule Hip ● ● ●

Ball-and-socket joint Head of the femur articulates with the acetabulum Good range of motion, but limited by the deep socket and strong ligaments ○ Acetabular labrum ○ Iliofemoral ligament ○ Pubofemoral ligament ○ Ischiofemoral ligament ○ Ligamentum teres

Elbow

● Hinge joint that allows flexion and extension only ● Radius and ulna articulate with the humerus ● Stability: ○ Annular ligament ○ Ulnar collateral ligament ○ Radial collateral ligament Sprains ● The ligaments reinforcing a joint are stretched or torn ● Partially torn ligaments slowly repair themselves ● Completely torn ligaments require prompt surgical repair Cartilage Injuries

● The snap and pop of overstressed cartilage ● Common aerobics injury ● Repaired with arthroscopic surgery Dislocation ● Occur when bones are forced out of alignment ● Usually accompanied by sprains, inflammation, and joint immobilization ● Caused by serious falls and are common sports injuries ● Subluxation – partial dislocation of a joint

Inflimationugy and Degernerative Conditions Arthritis ● More than 100 different types of inflammatory or degenerative diseases that damage the ● ● ● ●

joints Most widespread crippling disease in the U.S. Symptoms – pain, stiffness, and swelling of a joint Acute forms are caused by bacteria and are treated with antibiotics Chronic forms include ○ Osteoarthritis ■ 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 probably related to the normal aging process ■ Course: ● OA reflects the years of abrasion and compression causing increased production of metalloproteinase enzymes that break down cartilage ● As one ages, cartilage is destroyed more quickly than it is replaced ● The exposed bone ends thicken, enlarge, form bone spurs, and restrict movement ● Joints most affected are the cervical and lumbar spine, fingers, knuckles, knees, and hips ■ Treatment: ● OA is slow and irreversible ● Treatments include: ○ Mild pain relievers, along with moderate activity ○ Magnetic therapy ○ Glucosamine sulfate decreases pain and inflammation ○ Rheumatoid Arthritis■ Chronic, inflammatory, autoimmune disease of unknown cause, with an insidious onset ■ Usually arises between the ages of 40 to 50, but may occur at any age ■ Signs and symptoms include joint tenderness, anemia, osteoporosis, muscle atrophy, and cardiovascular problems ● The course of RA is marked with exacerbations and remissions ■ Course:

● RA begins with synovitis of the affected joint ● Inflammatory chemicals are inappropriately released

● Inflammatory blood cells migrate to the joint, causing swelling ● Inflamed synovial membrane thickens into a pannus ● Pannus erodes cartilage, scar tissue forms, articulating bone ends connect ● The end result, ankylosis, produces bent, deformed fingers ■ Treatment: ● Conservative therapy – aspirin, long-term use of antibiotics, and physical therapy ● Progressive treatment – anti-inflammatory drugs or immunosuppressants ● The drug Enbrel, a biological response modifier, neutralizes the harmful properties of inflammatory chemicals ○

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Gouty Arthritis ■ Deposition of uric acid crystals in joints and soft tissues, followed by an inflammation response ■ Typically, gouty arthritis affects the joint at the base of the great toe ■ Bodies don’t deal well with urine ■ In untreated gouty arthritis, the bone ends fuse and immobilize the joint ■ Treatment – colchicine, nonsteroidal anti-inflammatory drugs, and glucocorticoids...