8 Joints: Part B

Types of Synovial Joints Six types, based on shape of articular surfaces: Plane Hinge Pivot Condylar Saddle Ball-and-socket © 2013 Pearson Education, Inc.

Figure 8.7a The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the classification of synovial joints into six structural types. Plane joint Nonaxial movement Metacarpals Flat articular surfaces Gliding Carpals Examples: Intercarpal joints, intertarsal joints, joints between vertebral articular surfaces © 2013 Pearson Education, Inc.

Uniaxial movement Hinge joint Humerus Medial/lateral axis Cylinder Figure 8.7b The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the classification of synovial joints into six structural types. Hinge joint Uniaxial movement Humerus Medial/lateral axis Cylinder Trough Ulna Flexion and extension Examples: Elbow joints, interphalangeal joints © 2013 Pearson Education, Inc.

Uniaxial movement Pivot joint Vertical axis Sleeve (bone and ligament) Figure 8.7c The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the classification of synovial joints into six structural types. Pivot joint Uniaxial movement Vertical axis Sleeve (bone and ligament) Ulna Axle (rounded bone) Rotation Radius Examples: Proximal radioulnar joints, atlantoaxial joint © 2013 Pearson Education, Inc.

Figure 8.7d The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the classification of synovial joints into six structural types. Condylar joint Biaxial movement Medial/ lateral axis Anterior/ posterior axis Phalanges Oval articular surfaces Metacarpals Flexion and extension Adduction and abduction Examples: Metacarpophalangeal (knuckle) joints, wrist joints © 2013 Pearson Education, Inc.

Biaxial movement Saddle joint Medial/ Anterior/ lateral posterior axis Figure 8.7e The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the classification of synovial joints into six structural types. Saddle joint Biaxial movement Medial/ lateral axis Anterior/ posterior axis Metacarpal Ι Articular surfaces are both concave and convex Adduction and abduction Flexion and extension Trapezium Example: Carpometacarpal joints of the thumbs © 2013 Pearson Education, Inc.

Figure 8.7f The shapes of the joint surfaces define the types of movements that can occur at a synovial joint; they also determine the classification of synovial joints into six structural types. Ball-and-socket joint Multiaxial movement Cup (socket) Medial/lateral axis Anterior/posterior axis Vertical axis Scapula Spherical head (ball) Humerus Flexion and extension Adduction and abduction Rotation Examples: Shoulder joints and hip joints © 2013 Pearson Education, Inc.

Largest, most complex joint of body Knee Joint Largest, most complex joint of body Three joints surrounded by a single joint cavity Femoropatellar joint Plane joint Allows gliding motion during knee flexion Lateral and medial tibiofemoral joints Femoral condyles with lateral and medial menisci of tibia Allow flexion, extension, and some rotation when knee partly flexed PLAY A&P Flix™: Movement at the Knee Joint © 2013 Pearson Education, Inc.

Sagittal section through the right knee joint Figure 8.8a The knee joint. Tendon of quadriceps femoris Suprapatellar bursa Femur Articular capsule Patella Posterior cruciate ligament Subcutaneous prepatellar bursa Synovial cavity Lateral meniscus Lateral meniscus Infrapatellar fat pad Anterior cruciate ligament Deep infrapateller bursa Tibia Patellar ligament Sagittal section through the right knee joint © 2013 Pearson Education, Inc.

Superior view of the right tibia in the knee joint, showing Figure 8.8b The knee joint. Anterior Anterior cruciate ligament Articular cartilage on lateral tibial condyle Articular cartilage on medial tibial condyle Lateral meniscus Medial meniscus Posterior cruciate ligament Superior view of the right tibia in the knee joint, showing the menisci and cruciate ligaments © 2013 Pearson Education, Inc.

At least 12 associated bursae Capsule is reinforced by muscle tendons Knee Joint At least 12 associated bursae Capsule is reinforced by muscle tendons E.g., quadriceps and semimembranosus tendons Joint capsule is thin and absent anteriorly Anteriorly, quadriceps tendon gives rise to three broad ligaments Medial and lateral patellar retinacula Patellar ligament © 2013 Pearson Education, Inc.

Anterior view of right knee Figure 8.8c The knee joint. Quadriceps femoris muscle Tendon of quadriceps femoris muscle Patella Medial patellar retinaculum Lateral patellar retinaculum Tibial collateral ligament Fibular collateral ligament Patellar ligament Fibula Tibia Anterior view of right knee © 2013 Pearson Education, Inc.

Ligaments Stabilizing Knee Joint Capsular and extracapsular ligaments Help prevent hyperextension of knee Fibular and tibial collateral ligaments Oblique popliteal ligament Arcuate popliteal ligament © 2013 Pearson Education, Inc.

Posterior view of the joint capsule, including ligaments Figure 8.8d The knee joint. Tendon of adductor magnus Femur Articular capsule Medial head of gastrocnemius muscle Oblique popliteal ligament Lateral head of gastrocnemius muscle Popliteus muscle (cut) Bursa Fibular collateral ligament Tibial collateral ligament Arcuate popliteal ligament Tendon of semimembranosus muscle Tibia Posterior view of the joint capsule, including ligaments © 2013 Pearson Education, Inc.

Ligaments Stabilizing Knee Joint Intracapsular ligaments Prevent anterior-posterior displacement Reside outside synovial cavity Anterior cruciate ligament Attaches to anterior tibia Posterior cruciate ligament Attaches to posterior tibia © 2013 Pearson Education, Inc.

Animation: Rotatable Knee Figure 8.8e The knee joint. Fibular collateral ligament Lateral condyle of femur meniscus Tibia Fibula Anterior view of flexed knee, showing the cruciate ligaments (articular capsule removed, and quadriceps tendon cut and reflected distally) Posterior cruciate ligament Medial Tibial Patellar Patella Anterior Quadriceps tendon PLAY Animation: Rotatable Knee © 2013 Pearson Education, Inc.

Photograph of an opened knee joint; view similar to (e) Figure 8.8f 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) © 2013 Pearson Education, Inc.

Absorbs great vertical force Knee Joint Injuries Absorbs great vertical force Vulnerable to horizontal blows, especially laterally blows to extended knee Three C's Collateral ligaments Cruciate ligaments Cartilages © 2013 Pearson Education, Inc.

Lateral Medial Hockey puck Figure 8.9 A common knee injury. Lateral Medial Patella (outline) Hockey puck Tibial collateral ligament (torn) Medial meniscus (torn) Anterior cruciate ligament (torn) © 2013 Pearson Education, Inc.

Shoulder (Glenohumeral) Joint Ball-and-socket joint Head of humerus with glenoid cavity of scapula Most freely moving joint in body Stability sacrificed © 2013 Pearson Education, Inc.

Frontal section through right shoulder joint Figure 8.10a The shoulder joint. Acromion of scapula Coracoacromial ligament Synovial cavity of the glenoid cavity containing synovial fluid Subacromial bursa Fibrous layer of articular capsule Articular cartilage Tendon sheath Synovial membrane Fibrous layer of articular capsule Tendon of long head of biceps brachii muscle Humerus Frontal section through right shoulder joint PLAY Animation: Rotatable Shoulder © 2013 Pearson Education, Inc.

Cadaver photo corresponding to (a) Figure 8.10b 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) PLAY A&P Flix: Movement at the Glenohumeral joint: An Overview PLAY A&P Flix: Movement at the Glenohumeral joint (a) PLAY A&P Flix: Movement at the Glenohumeral joint (b) © 2013 Pearson Education, Inc.

Reinforcing ligaments Shoulder Joint Reinforcing ligaments Primarily on anterior aspect Coracohumeral ligament Helps support weight of upper limb Three glenohumeral ligaments Weak and sometimes absent © 2013 Pearson Education, Inc.

Shoulder Joint Reinforcing muscle tendons Tendon of long head of biceps brachii Travels through the intertubercular sulcus Secures humerus to glenoid cavity Four rotator cuff tendons encircle the shoulder joint Subscapularis Supraspinatus Infraspinatus Teres minor PLAY A&P Flix™: Rotator Cuff Muscles: An Overview (a) PLAY A&P Flix™: Rotator Cuff Muscles: An Overview (b) © 2013 Pearson Education, Inc.

Anterior view of right shoulder joint capsule Figure 8.10c The shoulder joint. Acromion Coracoid process Coracoacromial ligament Subacromial bursa Articular capsule reinforced by glenohumeral ligaments Coracohumeral ligament Greater tubercle of humerus Subscapular bursa Transverse humeral ligament Tendon of the subscapularis muscle Tendon sheath Scapula Tendon of long head of biceps brachii muscle Anterior view of right shoulder joint capsule © 2013 Pearson Education, Inc.

Lateral view of socket of right shoulder joint, humerus removed Figure 8.10d 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 © 2013 Pearson Education, Inc.

Anterior view of an opened shoulder joint Figure 8.10e The shoulder joint. Acromion (cut) Glenoid cavity of scapula Head of humerus Capsule of shoulder joint (opened) Muscle of rotator cuff (cut) Anterior view of an opened shoulder joint © 2013 Pearson Education, Inc.

Articulation of radius and ulna with humerus Hinge joint Elbow Joint Articulation of radius and ulna with humerus Hinge joint Primarily trochlear notch of ulna with trochlea of humerus Flexion and extension only PLAY A&P Flix™: Movement at the Elbow Joint © 2013 Pearson Education, Inc.

Median sagittal section through right elbow (lateral view) Figure 8.11a The elbow joint. Articular capsule Synovial membrane Humerus Synovial cavity Articular cartilage Fat pad Coronoid process Tendon of triceps muscle Tendon of brachialis muscle Ulna Bursa Trochlea Articular cartilage of the trochlear notch Median sagittal section through right elbow (lateral view) © 2013 Pearson Education, Inc.

Two capsular ligaments restrict side-to-side movement Elbow Joint Anular ligament Surrounds head of radius Two capsular ligaments restrict side-to-side movement Ulnar collateral ligament Radial collateral ligament © 2013 Pearson Education, Inc.

Lateral view of right elbow joint Figure 8.11b The elbow joint. Humerus Anular ligament Radius Lateral epicondyle Articular capsule Radial collateral ligament Olecranon Ulna Lateral view of right elbow joint © 2013 Pearson Education, Inc.

Medial view of right elbow Figure 8.11d The elbow joint. Articular capsule Anular ligament Humerus Coronoid process Medial epicondyle Ulnar collateral ligament Radius Ulna Medial view of right elbow PLAY Animation: Rotatable Elbow © 2013 Pearson Education, Inc.

Cadaver photo of medial view of right elbow Figure 8.11c The elbow joint. Humerus Anular ligament Medial epicondyle Radius Ulnar collateral ligament Articular capsule Coronoid process Ulna Cadaver photo of medial view of right elbow A&P Flix™: The Elbow Joint and Forearm: An overview PLAY © 2013 Pearson Education, Inc.

Ball-and-socket joint Head of the femur articulates with acetabulum Hip (Coxal) Joint Ball-and-socket joint Head of the femur articulates with acetabulum Good range of motion, but limited by the deep socket Rim of fibrocartilage - Acetabular labrum Enhances depth of socket so hip dislocations rare PLAY A&P Flix™: Movement at the Hip Joint: An Overview © 2013 Pearson Education, Inc.

Frontal section through the right hip joint Figure 8.12a The hip joint. Coxal (hip) bone Articular cartilage Ligament of the head of the femur (ligamentum teres) Acetabular labrum Femur Synovial cavity Articular capsule Frontal section through the right hip joint © 2013 Pearson Education, Inc.

Photo of the interior of the hip joint, lateral view Figure 8.12b 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 © 2013 Pearson Education, Inc.

Reinforcing ligaments Hip Joint Reinforcing ligaments Iliofemoral ligament Pubofemoral ligament Ischiofemoral ligament Ligamentum teres © 2013 Pearson Education, Inc.

Animation: Rotatable Hip Figure 8.12c The hip joint. Iliofemoral ligament Ischium Ischiofemoral ligament Greater trochanter of femur Posterior view of right hip joint, capsule in place PLAY Animation: Rotatable Hip © 2013 Pearson Education, Inc.

Anterior view of right hip joint, capsule in place Figure 8.12d The hip joint. Anterior inferior iliac spine Iliofemoral ligament Pubofemoral ligament Greater trochanter Anterior view of right hip joint, capsule in place © 2013 Pearson Education, Inc.

Temporomandibular Joint (TMJ) Mandibular condyle articulates with temporal bone Two types of movement Hinge—depression and elevation of mandible Gliding—e.g., side-to-side (lateral excursion) grinding of teeth Most easily dislocated joint in the body © 2013 Pearson Education, Inc.

Location of the joint in the skull Figure 8.13a The temporomandibular (jaw) joint. Mandibular fossa Articular tubercle Zygomatic process Infratemporal fossa External acoustic meatus Lateral ligament Articular capsule Ramus of mandible Location of the joint in the skull © 2013 Pearson Education, Inc.

Enlargement of a sagittal section through the joint Figure 8.13b The temporomandibular (jaw) joint. Articular disc Articular tubercle Mandibular fossa 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 © 2013 Pearson Education, Inc.

Lateral excursion: lateral (side-to-side) movements of the mandible Figure 8.13c The temporomandibular (jaw) joint. Outline of the mandibular fossa Superior view Lateral excursion: lateral (side-to-side) movements of the mandible © 2013 Pearson Education, Inc.

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 Perhaps meniscus grown from own stem cells in future © 2013 Pearson Education, Inc.

Femur Meniscus Tear in meniscus Tibia Figure 8.14 Arthroscopic photograph of a torn medial meniscus. Femur Meniscus Tear in meniscus Tibia © 2013 Pearson Education, Inc.

Common Joint Injuries Sprains Reinforcing ligaments stretched or torn Partial tears slowly repair heal Poor vascularization Three options if torn completely Ends sewn together Replaced with grafts Time and immobilization © 2013 Pearson Education, Inc.

Dislocations (luxations) Common Joint Injuries 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 © 2013 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, anti-inflammatory drugs Tendonitis Inflammation of tendon sheaths typically caused by overuse Symptoms and treatment similar to bursitis © 2013 Pearson Education, Inc.

Most widespread crippling disease in the U.S. 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 © 2013 Pearson Education, Inc.

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 3 times as many women as men Signs and symptoms include joint pain and swelling (usually bilateral), anemia, osteoporosis, muscle weakness, and cardiovascular problems © 2013 Pearson Education, Inc.

RA begins with synovitis of the affected joint Rheumatoid Arthritis RA begins with synovitis of the affected joint Inflammatory blood cells migrate to joint, release inflammatory chemicals that destroy tissues Synovial fluid accumulates  joint swelling and inflamed synovial membrane which thickens  pannus that clings to articular cartilage Pannus erodes cartilage, scar tissue forms and connects articulating bone ends (ankylosis) © 2013 Pearson Education, Inc.

Rheumatoid Arthritis: Treatment Disrupt destruction of joints by immune system Steroidal and nonsteroidal anti-inflammatory drugs decrease pain and inflammation Immune suppressants slow autoimmune reaction Some agents target tumor necrosis factor to block action of inflammatory chemicals Can replace joint with prosthesis © 2013 Pearson Education, Inc.

Figure 8.15 A hand deformed by rheumatoid arthritis. © 2013 Pearson Education, Inc.