Plane Joint Plane joints Plane joints Articular surfaces are essentially flat Articular surfaces are essentially flat Allow only slipping or gliding movements Allow only slipping or gliding movements Only examples of nonaxial joints Only examples of nonaxial joints Figure 8.7a

Types of Synovial Joints Hinge joints Hinge joints Cylindrical projections of one bone fits into a trough-shaped surface on another Cylindrical projections of one bone fits into a trough-shaped surface on another Motion is along a single plane Motion is along a single plane Uniaxial joints permit flexion and extension only Uniaxial joints permit flexion and extension only Examples: elbow and interphalangeal joints Examples: elbow and interphalangeal joints

Hinge Joints Figure 8.7b

Pivot Joints Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another Only uniaxial movement allowed Only uniaxial movement allowed Examples: joint between the axis and the dens, and the proximal radioulnar joint Examples: joint between the axis and the dens, and the proximal radioulnar joint

Pivot Joints Figure 8.7c

Condyloid or Ellipsoidal Joints Oval articular surface of one bone fits into a complementary depression in another Oval articular surface of one bone fits into a complementary depression in another Both articular surfaces are oval Both articular surfaces are oval Biaxial joints permit all angular motions Biaxial joints permit all angular motions Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints

Condyloid or Ellipsoidal Joints Figure 8.7d

Saddle Joints Similar to condyloid joints but allow greater movement Similar to condyloid joints but allow greater movement Each articular surface has both a concave and a convex surface Each articular surface has both a concave and a convex surface Example: carpometacarpal joint of the thumb Example: carpometacarpal joint of the thumb

Saddle Joints Figure 8.7e

Ball-and-Socket Joints A spherical or hemispherical head of one bone articulates with a cuplike socket of another A spherical or hemispherical head of one bone articulates with a cuplike socket of another Multiaxial joints permit the most freely moving synovial joints Multiaxial joints permit the most freely moving synovial joints Examples: shoulder and hip joints Examples: shoulder and hip joints

Ball-and-Socket Joints Figure 8.7f

Synovial Joints: Knee Largest and most complex joint of the body Largest and most complex joint of the body Allows flexion, extension, and some rotation Allows flexion, extension, and some rotation Three joints in one surrounded by a single joint cavity Three joints in one surrounded by a single joint cavity Femoropatellar joint Femoropatellar joint Lateral and medial tibiofemoral joints Lateral and medial tibiofemoral joints

Synovial Joints: Knee Ligaments and Tendons – Anterior View Tendon of the quadriceps femoris muscle Tendon of the quadriceps femoris muscle Lateral and medial patellar retinacula Lateral and medial patellar retinacula Fibular and tibial collateral ligaments Fibular and tibial collateral ligaments Patellar ligament Patellar ligament Figure 8.8c

Synovial Joints: Knee – Other Supporting Structures Anterior cruciate ligament Anterior cruciate ligament Posterior cruciate ligament Posterior cruciate ligament Medial meniscus (semilunar cartilage) Medial meniscus (semilunar cartilage) Lateral meniscus Lateral meniscus

Synovial Joints: Knee – Other Supporting Structures Figure 8.8b

Synovial Joints: Knee – Posterior Superficial View Adductor magnus tendon Adductor magnus tendon Articular capsule Articular capsule Oblique popliteal ligament Oblique popliteal ligament Arcuate popliteal ligament Arcuate popliteal ligament Semimembranosus tendon Semimembranosus tendon Figure 8.8e

Synovial Joints: Shoulder (Glenohumeral) Ball-and-socket joint in which stability is sacrificed to obtain greater freedom of movement 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 Head of humerus articulates with the glenoid fossa of the scapula

Synovial Joints: Elbow Hinge joint that allows flexion and extension only Hinge joint that allows flexion and extension only Radius and ulna articulate with the humerus Radius and ulna articulate with the humerus

Synovial Joints: Elbow Annular ligament Annular ligament Ulnar collateral ligament Ulnar collateral ligament Radial collateral ligament Radial collateral ligament Figure 8.10a

Synovial Joints: Elbow Figure 8.10b

Synovial Joints: Elbow Figure 8.10d

Synovial Joints: Shoulder Stability Weak stability is maintained by: Weak stability is maintained by: Thin, loose joint capsule Thin, loose joint capsule Four ligaments – coracohumeral, and three glenohumeral 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 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 Rotator cuff (four tendons) that encircles the shoulder joint and blends with the articular capsule

Synovial Joints: Shoulder Stability Figure 8.11a

Synovial Joints: Shoulder Stability Figure 8.11b

Synovial Joints: Hip (Coxal) Joint Ball-and-socket joint Ball-and-socket joint Head of the femur articulates with the acetabulum Head of the femur articulates with the acetabulum Good range of motion, but limited by the deep socket and strong ligaments Good range of motion, but limited by the deep socket and strong ligaments

Synovial Joints: Hip Stability Acetabular labrum Acetabular labrum Iliofemoral ligament Iliofemoral ligament Pubofemoral ligament Pubofemoral ligament Ischiofemoral ligament Ischiofemoral ligament Ligamentum teres Ligamentum teres Figure 8.12a

Synovial Joints: Hip Stability Figure 8.12c, d

Temporomandibular Joint (TMJ) Mandibular condyle articulate with the temporal bone Mandibular condyle articulate with the temporal bone Two types of movement Two types of movement Hinge – depression and elevation of mandible Hinge – depression and elevation of mandible Side to side – (lateral excursion) grinding of teeth Side to side – (lateral excursion) grinding of teeth

Temporomandibular Joint Figure 8.13a, b

Sprains The ligaments reinforcing a joint are stretched or torn The ligaments reinforcing a joint are stretched or torn Partially torn ligaments slowly repair themselves Partially torn ligaments slowly repair themselves Completely torn ligaments require prompt surgical repair Completely torn ligaments require prompt surgical repair

Cartilage Injuries The snap and pop of overstressed cartilage The snap and pop of overstressed cartilage Common aerobics injury Common aerobics injury Repaired with arthroscopic surgery Repaired with arthroscopic surgery

Dislocations Occur when bones are forced out of alignment Occur when bones are forced out of alignment Usually accompanied by sprains, inflammation, and joint immobilization Usually accompanied by sprains, inflammation, and joint immobilization Caused by serious falls and are common sports injuries Caused by serious falls and are common sports injuries Subluxation – partial dislocation of a joint Subluxation – partial dislocation of a joint

Inflammatory and Degenerative Conditions Bursitis Bursitis An inflammation of a bursa, usually caused by a blow or friction An inflammation of a bursa, usually caused by a blow or friction Symptoms are pain and swelling Symptoms are pain and swelling Treated with anti-inflammatory drugs; excessive fluid may be aspirated, ultimately surgery will be needed Treated with anti-inflammatory drugs; excessive fluid may be aspirated, ultimately surgery will be needed

Inflammatory and Degenerative Conditions Tendonitis Tendonitis Inflammation of tendon sheaths typically caused by overuse Inflammation of tendon sheaths typically caused by overuse Symptoms and treatment are similar to bursitis Symptoms and treatment are similar to bursitis

Arthritis More than 100 different types of inflammatory or degenerative diseases that damage the joints More than 100 different types of inflammatory or degenerative diseases that damage the joints Most widespread crippling disease in the U.S. Most widespread crippling disease in the U.S. Symptoms – pain, stiffness, and swelling of a joint Symptoms – pain, stiffness, and swelling of a joint Acute forms are caused by bacteria and are treated with antibiotics Acute forms are caused by bacteria and are treated with antibiotics Chronic forms include osteoarthritis, rheumatoid arthritis, and gouty arthritis Chronic forms include osteoarthritis, rheumatoid arthritis, and gouty arthritis

Osteoarthritis (OA) Most common chronic arthritis; often called “wear-and-tear” arthritis Most common chronic arthritis; often called “wear-and-tear” arthritis Affects women more than men Affects women more than men 85% of all Americans develop OA 85% of all Americans develop OA More prevalent in the aged, and is probably related to the normal aging process More prevalent in the aged, and is probably related to the normal aging process

Osteoarthritis: Course OA reflects the years of abrasion and compression causing increased production of metalloproteinase enzymes that break down cartilage 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 As one ages, cartilage is destroyed more quickly than it is replaced The exposed bone ends thicken, enlarge, form bone spurs, and restrict movement 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 Joints most affected are the cervical and lumbar spine, fingers, knuckles, knees, and hips

Osteoarthritis: Treatments OA is slow and irreversible OA is slow and irreversible Treatments include: Treatments include: Mild pain relievers, along with moderate activity Mild pain relievers, along with moderate activity Magnetic therapy Magnetic therapy Glucosamine sulfate decreases pain and inflammation Glucosamine sulfate decreases pain and inflammation

Rheumatoid Arthritis (RA) Chronic, inflammatory, autoimmune disease of unknown cause, with an insidious onset 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 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 Signs and symptoms include joint tenderness, anemia, osteoporosis, muscle atrophy, and cardiovascular problems The course of RA is marked with exacerbations and remissions The course of RA is marked with exacerbations and remissions

Rheumatoid Arthritis: Course RA begins with synovitis of the affected joint RA begins with synovitis of the affected joint Inflammatory chemicals are inappropriately released Inflammatory chemicals are inappropriately released Inflammatory blood cells migrate to the joint, causing swelling Inflammatory blood cells migrate to the joint, causing swelling

Rheumatoid Arthritis: Course Inflamed synovial membrane thickens into a pannus Inflamed synovial membrane thickens into a pannus Pannus erodes cartilage, scar tissue forms, articulating bone ends connect Pannus erodes cartilage, scar tissue forms, articulating bone ends connect The end result, ankylosis, produces bent, deformed fingers The end result, ankylosis, produces bent, deformed fingers

Rheumatoid Arthritis: Treatment Conservative therapy – aspirin, long-term use of antibiotics, and physical therapy Conservative therapy – aspirin, long-term use of antibiotics, and physical therapy Progressive treatment – anti-inflammatory drugs or immunosuppressants Progressive treatment – anti-inflammatory drugs or immunosuppressants The drug Enbrel, a biological response modifier, neutralizes the harmful properties of inflammatory chemicals The drug Enbrel, a biological response modifier, neutralizes the harmful properties of inflammatory chemicals

Gouty Arthritis Deposition of uric acid crystals in joints and soft tissues, followed by an inflammation response 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 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 In untreated gouty arthritis, the bone ends fuse and immobilize the joint Treatment – colchicine, nonsteroidal anti- inflammatory drugs, and glucocorticoids Treatment – colchicine, nonsteroidal anti- inflammatory drugs, and glucocorticoids

Developmental Aspects of Joints By embryonic week 8, synovial joints resemble adult joints By embryonic week 8, synovial joints resemble adult joints Few problems occur until late middle age Few problems occur until late middle age Advancing years take their toll on joints: Advancing years take their toll on joints: Ligaments and tendons shorten and weaken Ligaments and tendons shorten and weaken Intervertebral discs become more likely to herniate Intervertebral discs become more likely to herniate Most people in their 70s have some degree of OA Most people in their 70s have some degree of OA

Developmental Aspects of Joints Prudent exercise (especially swimming) that coaxes joints through their full range of motion is key to postponing joint problems Prudent exercise (especially swimming) that coaxes joints through their full range of motion is key to postponing joint problems