Joints: Modified by Dr. Par Mohammadian 8 Joints: Modified by Dr. Par Mohammadian

Classification of joints Overview Definitions Classification of joints Fibrous Cartilaginous Synovial Diseases/Injuries

Joints (Articulations) Site where two or more bones meet Functions of joints Give skeleton mobility Hold skeleton together Two classifications Functional Structural

Functional Classification of Joints Based on Amount of movement joint allows Three functional classifications: Synarthroses (syn=together; arthro=joint) — immovable joints Amphiarthroses (amphi=on both sides) — slightly movable joints Diarthroses (dia=through) — freely movable joints © 2013 Pearson Education, Inc.

Structural Classification of Joints Based on Material binding bones together Presence/absence of joint cavity Three structural classifications: Fibrous joints Cartilaginous joints Synovial joints

Classification of joints Fibrous Joints Suture Syndesmoses Gomphoses Cartilaginous Joints Synchondroses Sumpheses Synovial Joints General Structure

Bones joined by dense fibrous connective tissue; No joint cavity Fibrous Joints Bones joined by dense fibrous connective tissue; No joint cavity Most synarthrotic (immovable) Three types: Sutures Syndesmoses Gomphoses

Fibrous Joints: Sutures Joint held together with very short, interconnecting fibers, and bone edges interlock. Found only in the skull. Rigid, interlocking joints Immovable joints for protection of brain Contain short connective tissue fibers Allow for growth during youth In middle age, sutures ossify and fuse Called Synostoses Suture line Dense fibrous connective tissue

Fibrous Joints: Syndesmoses Syndesmosis Joint held together by a ligament. Fibrous tissue can vary in length, but is longer than in sutures. Bones connected by ligaments (bands of fibrous tissue) Fiber length varies so movement varies, i.e., Little to no movement at distal tibiofibular joint Large amount of movement at interosseous membrane connecting radius and ulna Fibula Tibia Ligament

Fibrous Joints: Gomphoses Gomphosis “Peg in socket” fibrous joint. Periodontal ligament holds tooth in socket. Peg-in-socket joints of teeth in alveolar sockets Fibrous connection is the periodontal ligament Socket of alveolar process Root of tooth Periodontal ligament

Structural Classification of Joints Fibrous Joints Suture Syndesmoses Gomphoses Cartilaginous Joints Synchondroses Sumpheses Synovial Joints General Structure

Bones united by cartilage No joint cavity Not highly movable Cartilaginous Joints Bones united by cartilage No joint cavity Not highly movable Two types: Synchondroses Symphyses

Bones united by hyaline cartilage Cartilaginous Joints: Synchondroses Bar/plate of hyaline cartilage unites bones Temporary epiphyseal plate joints Become synostoses after plate closure Cartilage of 1st rib with manubrium ~ All are synarthrotic Synchondroses Bones united by hyaline cartilage Sternum (manubrium) Epiphyseal plate (temporary hyaline cartilage joint) Joint between first rib and sternum (immovable)

Bones united by fibrocartilage Cartilaginous Joints: Symphyses Fibrocartilage unites bone Hyaline cartilage present as articular cartilage Strong, flexible amphiarthroses Symphyses Bones united by fibrocartilage Body of vertebra Fibrocartilaginous intervertebral disc (sandwiched between hyaline cartilage) Pubic symphysis

Structural Classification of Joints Fibrous Joints Suture Syndesmoses Gomphoses Cartilaginous Joints Synchondroses Sumpheses Synovial Joints General Structure

Synovial Joints Bones separated by fluid-filled joint cavity All are diarthrotic Include ~ all limb joints; most joints of body

Synovial Joints: General Structure Ligament Joint cavity (contains synovial fluid) Articular (hyaline) cartilage Fibrous layer Synovial membrane (secretes synovial fluid) Articular capsule Periosteum Synovial joints all have the following Articular cartilage Joint (synovial) cavity Articular capsule Synovial fluid Reinforcing ligaments

Synovial Joints: Friction-Reducing Structures Acromion of scapula Subacromial bursa Fibrous layer of articular capsule Tendon sheath Tendon of long head of biceps brachii muscle Frontal section through the right shoulder joint Joint cavity containing synovial fluid Articular cartilage Synovial membrane Fibrous layer Humerus Bursae –fibrous sacs lined with synovial membranes & containing synovial fluid Common where ligaments, muscles, skin, tendons, or bones rub together Tendon sheath – elongated bursa that wraps completely around a tendon

Synovial Joints: Movement The two muscle attachments across a joint are: Origin – attachment to the immovable bone Insertion – attachment to the movable bone Described as movement along transverse, frontal, or sagittal planes

Synovial Joints: Range of Motion Nonaxial—slipping movements only Uniaxial—movement in one plane Biaxial—movement in two planes Multiaxial—movement in or around all three planes

Movements of Joints 1. Gliding 2. Angular movements 3. Rotation Flexion, extension, hyperextension Abduction, adduction Circumduction 3. Rotation Medial and lateral rotation It is VERY important that you learn the terminology for movements of joints. Muscles act mainly to cause movement or fixation of a joint!!!!!!!

Gliding movements at the wrist One flat bone surface glides or slips over another similar surface Examples: Intercarpal joints Intertarsal joints Between articular processes of vertebrae Gliding Gliding movements at the wrist

Angular Movements Increase or decrease angle between two bones Hyperextension Extension Flexion Angular movements: flexion, extension, and hyperextension of the vertebral column Increase or decrease angle between two bones Movement along sagittal plane Flexion—decreases the angle of the joint Extension—increases the angle of the joint Hyperextension—excessive extension beyond normal range of motion Hyperextension Extension Flexion Angular movements: flexion, extension, and hyperextension of the neck

Figure 8.5d Movements allowed by synovial joints. Flexion Hyper- extension Extension Flexion Extension Angular movements: flexion, extension, and hyperextension at the shoulder and knee

Angular Movements Movement along frontal plane Abduction—movement away from the midline Adduction—movement toward the midline Circumduction Involves flexion, abduction, extension, and adduction of limb Limb describes cone in space Adduction Abduction Circumduction Angular movements: abduction, adduction, and circumduction of the upper limb at the shoulder

Rotation of the head, neck, and lower limb Turning of bone around its own long axis Toward midline or away from it Medial and lateral rotation Examples: Between C1 and C2 vertebrae Rotation of humerus and femur Rotation Lateral rotation Medial Rotation of the head, neck, and lower limb

Special Movements at Synovial Joints Supination and pronation of radius and ulna Dorsiflexion and plantar flexion of foot Inversion and eversion of foot Protraction and retraction Elevation and depression of mandible Opposition of thumb of mandible

Pronation (P) and supination (S) P S (radius rotates over ulna) Supination (radius and ulna are parallel) Pronation (P) and supination (S) P S Dorsiflexion and plantar flexion Plantar flexion Dorsiflexion

Inversion and eversion Opposition

Protraction and retraction of mandiblet Protraction of mandible Elevation of mandible Depression Elevation and depression

Types of Synovial Joints Six types, based on shape of articular surfaces: Plane Hinge Pivot Condylar Saddle Ball-and-socket

Plane joint Uniaxial movement Hinge joint Nonaxial movement Humerus Metacarpals Flat articular surfaces Gliding Carpals Examples: Intercarpal joints, intertarsal joints, joints between vertebral articular surfaces Hinge joint Uniaxial movement Humerus Medial/lateral axis Cylinder Trough Ulna Flexion and extension Examples: Elbow joints, interphalangeal joints

Condylar joint Uniaxial movement Pivot joint Biaxial movement Vertical axis Sleeve (bone and ligament) Ulna Axle (rounded bone) Rotation Radius Examples: Proximal radioulnar joints, atlantoaxial joint 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

Ball-and-socket joint 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 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

Largest and most complex joint of the body 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

Knee Ligaments and Tendons – Anterior View Tendon of the quadriceps femoris muscle Lateral and medial patellar retinacula Fibular and tibial collateral ligaments Patellar ligament

Knee – Other Supporting Structures 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 Anterior cruciate ligament Posterior cruciate ligament Medial meniscus (semilunar cartilage) Lateral meniscus Medial femoral condyle Anterior cruciate ligament Medial meniscus on medial tibial Patella Photograph of an opened knee joint; view similar to (e)

Figure 8.9 A common knee injury. Lateral Medial Patella (outline) Hockey puck Tibial collateral ligament (torn) Medial meniscus (torn) Anterior cruciate ligament (torn)

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 Acromion of scapula Coracoacromial ligament Subacromial bursa Fibrous layer of articular capsule Tendon sheath Tendon of long head of biceps brachii muscle Synovial membrane Humerus Articular cartilage Synovial cavity of the glenoid cavity containing synovial fluid

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

Anterior view of right shoulder joint capsule Acromion Coracoacromial ligament Subacromial bursa Coracohumeral Greater tubercle of humerus Transverse humeral Tendon sheath Tendon of long head of biceps brachii muscle Articular capsule reinforced by glenohumeral ligaments Subscapular Tendon of the subscapularis Scapula Coracoid process Anterior view of right shoulder joint capsule Lateral view of socket of right shoulder joint, humerus removed 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 Acromion

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. © 2013 Pearson Education, Inc.

Elbow Joint Articulation of radius and ulna with humerus Hinge joint Primarily trochlear notch of ulna with trochlea of humerus Flexion and extension only 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)

Lateral view of right elbow joint Anular ligament Surrounds head of radius Two capsular ligaments restrict side-to-side movement Ulnar collateral ligament Radial collateral ligament Humerus Lateral epicondyle Articular capsule Radial collateral ligament Olecranon Anular Radius Ulna Lateral view of right elbow joint

Medial view of right elbow Articular capsule Anular ligament Coronoid process Radius Humerus Medial epicondyle Ulnar collateral Ulna Medial view of right elbow Anular ligament Radius Articular capsule Coronoid process Humerus Medial epicondyle Ulnar collateral Ulna

Hip (Coxal) Joint 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 Ligament of the head of the femur (ligamentum teres) Coxal (hip) bone Articular cartilage Acetabular labrum Femur Frontal section through the right hip joint Synovial cavity Articular capsule

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. © 2013 Pearson Education, Inc.

Hip Stability Acetabular labrum Iliofemoral ligament Pubofemoral ligament Ischiofemoral ligament Ligamentum teres

Synovial Joints: Hip Stability

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

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

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

Arthritis >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

Osteoarthritis (OA) Common, irreversible, degenerative (''wear-and-tear'') arthritis May reflect excessive release of enzymes that break down articular cartilage By age 85 half of Americans develop OA, more women than men Probably related to normal aging process

Treatment: moderate activity, mild pain relievers, capsaicin creams Osteoarthritis (OA) More cartilage is destroyed than replaced in badly aligned or overworked joints Exposed bone ends thicken, enlarge, form bone spurs, and restrict movement Treatment: moderate activity, mild pain relievers, capsaicin creams Glucosamine, chondroitin sulfate, and nutritional supplements not effective

Rheumatoid Arthritis (RA) Chronic, inflammatory, autoimmune disease of unknown cause (Immune system attacks own cells) between ages 40-50, but may occur at any age; affects 3x as many women as men Signs and symptoms include joint pain and swelling (usually bilateral), anemia, osteoporosis, muscle weakness, and cardiovascular problems

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)

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

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