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Chapter 8 Part B Joints © Annie Leibovitz/Contact Press Images © 2016 Pearson Education, Inc. PowerPoint® Lecture Slides prepared by Karen Dunbar Kareiva Ivy Tech Community College 8.5 Selected Synovial Joints • Synovial joints are diverse • All have general features, but some also have unique structural features, abilities, and weaknesses • Five main synovial joints – Knee – Shoulder – Elbow – Hip – Jaw © 2016 Pearson Education, Inc. Knee Joint • Largest, most complex joint of body • Consists of three joints surrounded by single cavity 1. Femoropatellar joint • Plane joint • Allows gliding motion during knee flexion 2. Lateral joint and 3. Medial joint • Lateral and medial joints together are called tibiofemoral joint • Joint between femoral condyles and lateral and medial menisci of tibia • Hinge joint that allows flexion, extension, and some rotation when knee partly flexed © 2016 Pearson Education, Inc. Figure 8.7a The knee joint. Femur Articular capsule Tendon of quadriceps femoris Suprapatellar bursa Posterior cruciate ligament Patella Subcutaneous prepatellar bursa Lateral meniscus Synovial cavity Anterior cruciate ligament Tibia Lateral meniscus Infrapatellar fat pad Deep infrapatellar bursa Patellar ligament Sagittal section through the right knee joint © 2016 Pearson Education, Inc. Figure 8.7b The knee joint. Anterior Anterior cruciate ligament Articular cartilage on lateral tibial condyle Articular cartilage on medial tibial condyle Medial meniscus Lateral meniscus Posterior cruciate ligament Superior view of the right tibia in the knee joint, showing the menisci and cruciate ligaments © 2016 Pearson Education, Inc. Knee Joint (cont.) • Joint capsule is thin and absent anteriorly • Anteriorly, quadriceps tendon gives rise to three broad ligaments that run from patella to tibia – Medial and lateral patellar retinacula that flank the patellar ligament • Doctors tap patellar ligament to test knee-jerk reflex • At least 12 bursae associated with knee joint © 2016 Pearson Education, Inc. Figure 8.7c The knee joint. Quadriceps femoris muscle Tendon of quadriceps femoris muscle Patella Lateral patellar retinaculum Fibular collateral ligament Fibula Medial patellar retinaculum Tibial collateral ligament Patellar ligament Tibia Anterior view of right knee © 2016 Pearson Education, Inc. Knee Joint (cont.) • Capsular, extracapsular, or intracapsular ligaments act to stabilize knee joint • Capsular and extracapsular ligaments help prevent hyperextension of knee – Fibular and tibial collateral ligaments: prevent rotation when knee is extended – Oblique popliteal ligament: stabilizes posterior knee joint – Arcuate popliteal ligament: reinforces joint capsule posteriorly © 2016 Pearson Education, Inc. Figure 8.7d The knee joint. Tendon of adductor magnus Medial head of gastrocnemius muscle Popliteus muscle (cut) Tibial collateral ligament Tendon of semimembranosus muscle Femur Articular capsule Oblique popliteal ligament Lateral head of gastrocnemius muscle Bursa Fibular collateral ligament Arcuate popliteal ligament Tibia Posterior view of the joint capsule, including ligaments © 2016 Pearson Education, Inc. Knee Joint (cont.) • Intracapsular ligaments reside within capsule, but outside synovial cavity • Help to prevent anterior-posterior displacement – Anterior cruciate ligament (ACL) • Attaches to anterior tibia • Prevents forward sliding of tibia and stops hyperextension of knee – Posterior cruciate ligament • Attaches to posterior tibia • Prevents backward sliding of tibia and forward sliding of femur © 2016 Pearson Education, Inc. Figure 8.7e The knee joint. Fibular collateral ligament Lateral condyle of femur Posterior cruciate ligament Medial condyle Tibial collateral ligament Lateral meniscus Anterior cruciate ligament Tibia Medial meniscus Patellar ligament Fibula Patella Quadriceps tendon Anterior view of flexed knee, showing the cruciate ligaments (articular capsule removed, and quadriceps tendon cut and reflected distally) © 2016 Pearson Education, Inc. Figure 8.7f The knee joint. Medial femoral condyle Anterior cruciate ligament Medial meniscus on medial tibial condyle Patella Photograph of an opened knee joint; view similar to (e) © 2016 Pearson Education, Inc. Clinical – Homeostatic Imbalance 8.1 • Knee absorbs great amount of vertical force; however, it is vulnerable to horizontal blows – Common knee injuries involved the 3 C’s: • Collateral ligaments • Cruciate ligaments • Cartilages (menisci) – Lateral blows to extended knee can result in tears in tibial collateral ligament, medial meniscus, and anterior cruciate ligament – Injuries affecting just ACL are common in runners who change direction, twisting ACL – Surgery usually needed for repairs © 2016 Pearson Education, Inc. Figure 8.8 The “unhappy triad:” ruptured ACL, ruptured tibial collateral ligament, and torn meniscus. Lateral Hockey puck Medial Patella (outline) Tibial collateral ligament (torn) Medial meniscus (torn) Anterior cruciate ligament (torn) © 2016 Pearson Education, Inc. Shoulder (Glenohumeral) Joint • Most freely moving joint in body • Stability is sacrificed for freedom of movement • Ball-and-socket joint – Large, hemispherical head of humerus fits in small, shallow glenoid cavity of scapula • Like a golf ball on a tee • Articular capsule enclosing cavity is also thin and loose – Contributes to freedom of movement © 2016 Pearson Education, Inc. Figure 8.9a The shoulder joint. Acromion of scapula Coracoacromial ligament Subacromial bursa Synovial cavity of the glenoid cavity containing synovial fluid Fibrous layer of articular capsule Articular cartilage Tendon sheath Synovial membrane Tendon of long head of biceps brachii muscle Fibrous layer of articular capsule Humerus Frontal section through right shoulder joint © 2016 Pearson Education, Inc. Figure 8.9b The shoulder joint. Synovial cavity of the glenoid cavity containing synovial fluid Articular cartilage Fibrous layer of articular capsule Humerus Cadaver photo corresponding to (a) © 2016 Pearson Education, Inc. Shoulder (Glenohumeral) Joint (cont.) • Glenoid labrum: fibrocartilaginous rim around glenoid cavity – Helps to add depth to shallow cavity – Cavity still only holds one-third of head of humerus • Reinforcing ligaments – Primarily on anterior aspect – Coracohumeral ligament • Helps support weight of upper limb – Three glenohumeral ligaments • Strengthen anterior capsule, but are weak support © 2016 Pearson Education, Inc. Figure 8.9c The shoulder joint. Acromion Coracoacromial ligament Subacromial bursa Coracohumeral ligament Transverse humeral ligament Tendon sheath Tendon of long head of biceps brachii muscle Coracoid process Articular capsule reinforced by glenohumeral ligaments Subscapular bursa Tendon of the subscapularis muscle Scapula Anterior view of right shoulder joint capsule © 2016 Pearson Education, Inc. Figure 8.9d The shoulder joint. Acromion Coracoid process Articular capsule Glenoid cavity Glenoid labrum Tendon of long head of biceps brachii muscle Glenohumeral ligaments Tendon of the subscapularis muscle Scapula Posterior Anterior Lateral view of socket of right shoulder joint, humerus removed © 2016 Pearson Education, Inc. Shoulder (Glenohumeral) Joint (cont.) • Reinforcing muscle tendons contribute most to joint stability – Tendon of long head of biceps brachii muscle is “superstabilizer” • Travels through intertubercular sulcus • Secures humerus to glenoid cavity – Four rotator cuff tendons encircle the shoulder joint • • • • Subscapularis Supraspinatus Infraspinatus Teres minor © 2016 Pearson Education, Inc. Figure 8.9c The shoulder joint. Acromion Coracoacromial ligament Subacromial bursa Coracohumeral ligament Transverse humeral ligament Tendon sheath Tendon of long head of biceps brachii muscle Coracoid process Articular capsule reinforced by glenohumeral ligaments Subscapular bursa Tendon of the subscapularis muscle Scapula Anterior view of right shoulder joint capsule © 2016 Pearson Education, Inc. Figure 8.9d The shoulder joint. Acromion Coracoid process Articular capsule Glenoid cavity Glenoid labrum Tendon of long head of biceps brachii muscle Glenohumeral ligaments Tendon of the subscapularis muscle Scapula Posterior Anterior Lateral view of socket of right shoulder joint, humerus removed © 2016 Pearson Education, Inc. Figure 8.9e The shoulder joint. Acromion (cut) Glenoid cavity of scapula Rotator cuff muscles (cut) Glenoid labrum Capsule of shoulder joint (opened) Head of humerus Posterior view of an opened right shoulder joint © 2016 Pearson Education, Inc. Elbow Joint • Humerus articulates with radius and ulna • Hinge joint formed primarily from trochlear notch of ulna articulating with trochlea of humerus – Allows for flexion and extension only • Anular ligament surrounds head of radius • Two capsular ligaments restrict side-to-side movement – Ulnar collateral ligament – Radial collateral ligament © 2016 Pearson Education, Inc. Figure 8.10a The elbow joint. Articular capsule Synovial membrane Humerus Synovial cavity Articular cartilage Fat pad Tendon of triceps muscle Bursa Coronoid process Tendon of brachialis muscle Ulna Trochlea Articular cartilage of the trochlear notch Median sagittal section through right elbow (lateral view) © 2016 Pearson Education, Inc. Figure 8.10b The elbow joint. Humerus Anular ligament Lateral epicondyle Radius Articular capsule Radial collateral ligament Olecranon Ulna Lateral view of right elbow joint © 2016 Pearson Education, Inc. Figure 8.10c The elbow joint. Humerus Anular ligament Medial epicondyle Radius Articular capsule Coronoid process of ulna Ulna Ulnar collateral ligament Cadaver photo of medial view of right elbow © 2016 Pearson Education, Inc. Figure 8.10d The elbow joint. Articular capsule Anular ligament Humerus Coronoid process Radius Medial epicondyle Ulnar collateral ligament Ulna Medial view of right elbow © 2016 Pearson Education, Inc. Hip (Coxal) Joint • Ball-and-socket joint • Large, spherical head of the femur articulates with deep cup-shaped acetabulum • Good range of motion, but limited by the deep socket – Acetabular labrum: rim of fibrocartilage that enhances depth of socket (hip dislocations are rare) © 2016 Pearson Education, Inc. Figure 8.11a The hip joint. Articular cartilage Acetabular labrum Hip (coxal) bone Ligament of the head of the femur (ligamentum teres) Femur Synovial cavity Articular capsule Frontal section through the right hip joint © 2016 Pearson Education, Inc. Figure 8.11b The hip joint. Acetabular labrum Synovial membrane Ligament of the head of the femur (ligamentum teres) Head of femur Articular capsule (cut) Photo of the interior of the hip joint, lateral view © 2016 Pearson Education, Inc. Hip (Coxal) Joint (cont.) • Reinforcing ligaments include: – Iliofemoral ligament – Pubofemoral ligament – Ischiofemoral ligament – Ligament of head of femur (ligamentum teres) • Slack during most hip movements, so not important in stabilizing • Does contain artery that supplies head of femur • Greatest stability comes from deep ball-andsocket joint © 2016 Pearson Education, Inc. Figure 8.11c The hip joint. Ischium Iliofemoral ligament Ischiofemoral ligament Greater trochanter of femur Posterior view of right hip joint, capsule in place © 2016 Pearson Education, Inc. Figure 8.11d The hip joint. Anterior inferior iliac spine Greater trochanter Iliofemoral ligament Pubofemoral ligament Anterior view of right hip joint, capsule in place © 2016 Pearson Education, Inc. Temporomandibular Joint (TMJ) • Jaw joint is a modified hinge joint • Mandibular condyle articulates with temporal bone – Posterior temporal bone forms mandibular fossa, while anterior portion forms articular tubercle • Articular capsule thickens into strong lateral ligament © 2016 Pearson Education, Inc. Temporomandibular Joint (TMJ) (cont.) • Two types of movement – Hinge: depression and elevation of mandible – Gliding: side-to-side (lateral excursion) grinding of teeth • Most easily dislocated joint in the body © 2016 Pearson Education, Inc. Figure 8.12a The temporomandibular (jaw) joint. Mandibular fossa Articular tubercle Zygomatic process Infratemporal fossa External acoustic meatus Articular capsule Lateral ligament Ramus of mandible Location of the joint in the skull © 2016 Pearson Education, Inc. Figure 8.12b The temporomandibular (jaw) joint. Articular disc Mandibular fossa Articular tubercle Superior joint cavity Articular capsule Synovial membranes Condylar process of mandible Ramus of mandible Inferior joint cavity Enlargement of a sagittal section through the joint © 2016 Pearson Education, Inc. Figure 8.12c The temporomandibular (jaw) joint. Superior view Outline of the mandibular fossa Lateral excursion: lateral (side-to-side) movements of the mandible © 2016 Pearson Education, Inc. Clinical – Homeostatic Imbalance 8.2 • Dislocation of TMJ is most common because of shallow socket of joint • Almost always dislocates anteriorly, causing mouth to remain open – To realign, physician must push mandible back into place © 2016 Pearson Education, Inc. Clinical – Homeostatic Imbalance 8.2 • Symptoms: ear and face pain, tender muscles, popping sounds when opening mouth, joint stiffness • Usually caused by grinding teeth, but can also be due to jaw trauma or poor occlusion of teeth – Treatment for grinding teeth includes bite plate – Relaxing jaw muscles helps © 2016 Pearson Education, Inc. 8.6 Disorders of Joints 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 Partial menisci removal renders joint less stable but mobile; complete removal leads to osteoarthritis – Meniscal transplant possible in younger patients – Perhaps meniscus grown from own stem cells in future © 2016 Pearson Education, Inc. Figure 8.13 Arthroscopic photograph of a torn medial meniscus. Femur Meniscus Tear in meniscus Tibia © 2016 Pearson Education, Inc. Common Joint Injuries (cont.) • Sprains – Reinforcing ligaments are stretched or torn – Common sites are ankle, knee, and lumbar region of back – Partial tears repair very slowly because of poor vascularization – Three options if torn completely • Ends of ligaments can be sewn together • Replaced with grafts • Just allow time and immobilization for healing © 2016 Pearson Education, Inc. Common Joint Injuries (cont.) • Dislocations (luxations) – Bones forced out of alignment – Accompanied by sprains, inflammation, and difficulty moving joint – Caused by serious falls or contact sports – Must be reduced to treat • Subluxation: partial dislocation of a joint © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions • Bursitis – Inflammation of bursa, usually caused by blow or friction – Treated with rest and ice and, if severe, antiinflammatory drugs • Tendonitis – Inflammation of tendon sheaths, typically caused by overuse – Symptoms and treatment similar to those of bursitis © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Arthritis – >100 different types of inflammatory or degenerative diseases that damage joints – Most widespread crippling disease in the U.S. – Symptoms: pain, stiffness, and swelling of joint – Acute forms: caused by bacteria, treated with antibiotics – Chronic forms: osteoarthritis, rheumatoid arthritis, and gouty arthritis © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Osteoarthritis (OA) – Most common type of arthritis – Irreversible, degenerative (“wear-and-tear”) arthritis – May reflect excessive release of enzymes that break down articular cartilage • Cartilage is broken down faster than it is replaced • Bone spurs (osteophytes) may form from thickened ends of bones – By age 85, half of Americans develop OA, more women than men © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Osteoarthritis (OA) (cont.) – OA is usually part of normal aging process – Joints may be stiff and make crunching noise referred to as crepitus, especially upon rising – Treatment: moderate activity, mild pain relievers, capsaicin creams • Glucosamine, chondroitin sulfate, and nutritional supplements not effective © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Rheumatoid arthritis (RA) – Chronic, inflammatory, autoimmune disease of unknown cause • Immune system attacks own cells – Usually arises between ages 40 and 50, but may occur at any age; affects three times as many women as men – Signs and symptoms include joint pain and swelling (usually bilateral), anemia, osteoporosis, muscle weakness, and cardiovascular problems © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Rheumatoid arthritis (RA) (cont.) – RA begins with inflammation of synovial membrane (synovitis) of affected joint – Inflammatory blood cells migrate to joint, release inflammatory chemicals that destroy tissues – Synovial fluid accumulates, causing joint swelling – Inflamed synovial membrane thickens into abnormal pannus tissue that clings to articular cartilage – Pannus erodes cartilage, scar tissue forms and connects articulating bone ends (ankylosis) © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Rheumatoid arthritis (RA) (cont.) – Treatment includes steroidal and nonsteroidal anti-inflammatory drugs to decrease pain and inflammation – Disruption of destruction of joints by immune system • Immune suppressants slow autoimmune reaction • Some agents target tumor necrosis factor to block action of inflammatory chemicals – Can replace joint with prosthesis © 2016 Pearson Education, Inc. Figure 8.14 A hand deformed by rheumatoid arthritis. © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Gouty arthritis – Deposition of uric acid crystals in joints and soft tissues, followed by inflammation – More common in men – Typically affects joint at base of great toe – In untreated gouty arthritis, bone ends fuse and immobilize joint – Treatment: drugs, plenty of water, avoidance of alcohol and foods high in purines, such as liver, kidneys, and sardines © 2016 Pearson Education, Inc. Inflammatory and Degenerative Conditions (cont.) • Lyme disease – Caused by bacteria transmitted by tick bites – Symptoms: skin rash, flu-like symptoms, and foggy thinking – May lead to joint pain and arthritis – Treatment • Long course of antibiotics © 2016 Pearson Education, Inc. Developmental Aspects of Joints • By embryonic week 8, synovial joints resemble adult joints • Joint’s size, shape, and flexibility modified by use – Active joints have thicker capsules and ligaments © 2016 Pearson Education, Inc. Developmental Aspects of Joints • 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 © 2016 Pearson Education, Inc.