Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 8 Joints Part B

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Joints  Although all synovial joints have structural features in common they do not have a common structural plan.  Base on the shape of the articular surfaces can be classified in 6 major categories:  1.- Planes  2.- Hinge  3.- Pivot  4.- Condyloid  5.- Saddle  6.- Ball and socked joints

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Types of Synovial Joints  Plane joints  Articular surfaces are essentially flat  Allow only slipping or gliding movements  Only examples of nonaxial joints Figure 8.7a

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Types of Synovial Joints  Hinge joints  Cylindrical projections of one bone fits into a trough-shaped surface on another  Motion is along a single plane  Uniaxial joints permit flexion and extension only  Examples: elbow and interphalangeal joints

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Types of Synovial Joints Figure 8.7b

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pivot Joints  Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another  Only uniaxial movement allowed  Examples: joint between the axis and the dens, and the proximal radioulnar joint

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pivot Joints Figure 8.7c

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Condyloid, or Ellipsoidal, Joints  Oval articular surface of one bone fits into a complementary depression in another  Both articular surfaces are oval  Biaxial joints permit all angular motions  Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Condyloid, or Ellipsoidal, Joints Figure 8.7d

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Saddle Joints  Similar to condyloid joints but allow greater movement  Each articular surface has both a concave and a convex surface  Example: carpometacarpal joint of the thumb

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Saddle Joints Figure 8.7e

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Ball-and-Socket Joints  A spherical or hemispherical head of one bone articulates with a cuplike socket of another  Multiaxial joints permit the most freely moving synovial joints  Examples: shoulder and hip joints

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Ball-and-Socket Joints Figure 8.7f

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Knee  Largest and most complex joint of the body  Allows flexion, extension, and some rotation  Three joints in one surrounded by a single joint cavity  Femoropatellar  Lateral and medial tibiofemoral joints

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Tendon of the quadriceps femoris muscle  Lateral and medial patellar retinacula  Fibular and tibial collateral ligaments  Patellar ligament Synovial Joints: Knee Ligaments and Tendons – Anterior View Figure 8.8c

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Anterior cruciate ligament  Posterior cruciate ligament  Medial meniscus (semilunar cartilage)  Lateral meniscus Synovial Joints: Knee – Other Supporting Structures

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 8.8b Synovial Joints: Knee – Other Supporting Structures

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Adductor magnus tendon  Articular capsule  Oblique popliteal ligament  Arcuate popliteal ligament  Semimembranosus tendon Figure 8.8e Synovial Joints: Knee – Posterior Superficial View

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Shoulder (Glenohumeral)  Ball-and-socket joint in which stability is sacrificed to obtain greater freedom of movement  Head of humerus articulates with the glenoid fossa of the scapula

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Homeostatic Imbalance  Lateral blows to the tibial collateral ligament and the medial meniscus attached to it, as well as the anterior cruciate ligament (Fig 8.9)  50% football players have this injury

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Shoulder Stability  Weak stability is maintained 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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Shoulder Stability Figure 8.10a

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Shoulder Stability Figure 8.10b

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Hip (Coxal) Joint  Hip joint like the shoulder is a 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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Acetabular labrum  Iliofemoral ligament  Pubofemoral ligament  Ischiofemoral ligament  Ligamentum teres Figure 8.11a Synovial Joints: Hip Stability

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Hip Stability Figure 8.11c, d

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Elbow  Our upper limbs are flexible extensions that permit us to reach out and manipulate things in our environment. Beside the shoulder joint the most prominent of the upper limb joint is the elbow  Hinge joint that allows flexion and extension only  Radius and ulna articulate with the humerus

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Annular ligament  Ulnar collateral ligament  Radial collateral ligament Figure 8.12a Synovial Joints: Elbow Stability

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 8.12b, d Synovial Joints: Elbow Stability

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Homeostatic Imbalance of joints (pp 272)  The most common trauma-induces joint injuries are: sprains and dislocations

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sprains  The ligaments reinforcing a joint are stretched or torn  Partially torn ligaments slowly repair themselves  Completely torn ligaments require prompt surgical repair

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cartilage Injuries  The snap and pop of overstressed cartilage  Common aerobics injury  Repaired with arthroscopic surgery

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dislocations (luxations)  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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Inflammatory and Degenerative Conditions  Bursitis  An inflammation of a bursa, usually caused by a blow or friction  Symptoms are pain and swelling  Treated with anti-inflammatory drugs; excessive fluid may be aspirated  Tendonitis  Inflammation of tendon sheaths typically caused by overuse  Symptoms and treatment are similar to bursitis

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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, rheumatoid arthritis, and gouty arthritis

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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 probably related to the normal aging process

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Osteoarthritis: 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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Osteoarthritis: Treatments  OA is slow and irreversible  Treatments include:  Mild pain relievers, along with moderate activity  Magnetic therapy  Glucosamine sulfate decreases pain and inflammation

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Rheumatoid Arthritis (RA)  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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Rheumatoid Arthritis: 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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Rheumatoid Arthritis: 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

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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  In untreated gouty arthritis, the bone ends fuse and immobilize the joint  Treatment – colchicine, nonsteroidal anti- inflammatory drugs, and glucocorticoids

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Developmental Aspects of Joints  By embryonic week 8, synovial joints resemble adult joints  Few problems occur until late middle age  Advancing years take their toll on joints:  Ligaments and tendons shorten and weaken  Intervertebral discs become more likely to herniate  Most people in their 70s have some degree of OA  Prudent exercise (especially swimming) that coaxes joints through their full range of motion is key to postponing joint problems