Joints (Articulations) Functions of joints Classifying Joints: Functional or Structural Naming Movements of Bones Around Joints Types of Joints Based on Movement Selected Key Joints: Shoulder, Elbow, Hip, Knee Joint Injuries Chronic Joint Conditions: Arthritis

Types of Synovial Joints Based on Shape

Plain hinge joints pivot on condyloid saddle ball-sockets.

Joints (Articulations) Functions of joints Classifying Joints: Functional or Structural Naming Movements of Bones Around Joints Types of Joints Based on Movement Selected Key Joints: Shoulder, Elbow, Hip, Knee Joint Injuries Chronic Joint Conditions: Arthritis

Shoulder (Glenohumeral) Joint Bones and features involved Head of humerus and glenoid fossa of the scapula Type of joint Ball-and-socket joint Stability/strength of joint Coracohumeral ligament supports the weight of the upper limb Three glenohumeral ligaments—weak anterior reinforcements Reinforced by tendon of the long head of biceps and 4 rotator cuff tendons Four rotator cuff tendons encircle the shoulder joint: Stability is sacrificed for greater freedom of movement Allowable movements Diarthrotic Flexion, extension, adduction, abduction, medial and lateral rotation

Elbow Joint Bones and features involved Radius and ulna articulate with the humerus Hinge at trochlear notch of ulna and trochlea of humerus Type of joint Hinge joint Stability/strength of joint Anular ligament —surrounds head of radius Two capsular ligaments restrict side- to-side movement: Ulnar collateral ligament Radial collateral ligament Allowable movements Diarthrotic Flexion and extension only

Hip (Coxal) Joint Bones and features involved Head of the femur articulates with the acetabulum of the pelvis Type of joint Ball-and-socket joint Stability/strength of joint 4 Reinforcing ligaments: Iliofemoral ligament Pubofemoral ligament Ischiofemoral ligament Ligamentum teres Allowable movements Flexion, extension, rotation, adduction, abduction, circumduction Good range of motion, but limited by the deep socket Acetabular labrum (ring of cartilage around cavity—enhances depth of socket, difficult to dislocate

Knee Joint Bones and features involved Largest, most complex joint of body Three joints surrounded by a single joint cavity: femoropatellar, lateral and medial tibiofemoral joints Type of joint Femoropatellar joint - plane joint with gliding Lateral and medial tibiofemoral hinge joints between the femoral condyles and the C-shaped lateral and medial menisci (semilunar cartilages) of the tibia Stability/strength of joint Capsule is reinforced by muscle tendons: Quadriceps and semimembranosus tendons Joint capsule is thin and absent anteriorly Anteriorly, the quadriceps tendon gives rise to patellar ligament Capsular and extracapsular ligaments prevent hyperextension Intracapsular ligaments Allowable movements Diarthrotic Allows flexion, extension, and some rotation when knee is partly flexed

Joints (Articulations) Functions of joints Classifying Joints: Functional or Structural Naming Movements of Bones Around Joints Types of Joints Based on Movement Selected Key Joints: Shoulder, Elbow, Hip, Knee Joint Injuries Chronic Joint Conditions: Arthritis

Common Joint Injuries Sprains The ligaments are stretched or torn Partial tears slowly repair themselves Complete ruptures require prompt surgical repair Cartilage tears Due to compression and shear stress Fragments may cause joint to lock or bind Cartilage rarely repairs itself Repaired with arthroscopic surgery Dislocations (luxations) Occur when bones are forced out of alignment Accompanied by sprains, inflammation, and joint immobilization Caused by serious falls or playing sports Subluxation—partial dislocation of a joint

Inflammatory and Degenerative Conditions Bursitis An inflammation of a bursa, usually caused by a 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

Joints (Articulations) Functions of joints Classifying Joints: Functional or Structural Naming Movements of Bones Around Joints Types of Joints Based on Movement Selected Key Joints: Shoulder, Elbow, Hip, Knee Joint Injuries Chronic Joint Conditions: Arthritis

Lyme Disease: Acute Arthritis Caused by bacteria transmitted by the bites of ticks Symptoms: skin rash, flu-like symptoms, and foggy thinking May lead to joint pain and arthritis Treatment: antibiotics

Clinical Forms of Arthritis (Three Chronic Types) 1. Osteoarthritis Most common chronic arthritis Irreversible, degenerative (“wear-and-tear”) arthritis 85% of all Americans develop OA, more women than men Probably related to the normal aging process 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 and chondroitin sulfate 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 a joint Acute forms: caused by bacteria, treated with antibiotics Chronic forms: osteoarthritis, rheumatoid arthritis, and gouty arthritis

2. Rheumatoid arthritis Chronic, inflammatory, autoimmune disease of unknown cause Begins years of age, more common in women 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 Inflammatory blood cells migrate to the joint, release inflammatory chemicals, cartilage erodes, scar tissue forms, bone ends connect. Treatment: aspirin, long-term use of antibiotics, and physical therapy; anti-inflammatory drugs or immunosuppressants; new biological response modifier drugs neutralize inflammatory chemicals Clinical Forms of Chronic Arthritis

3. Gouty Arthritis Inflammation of joints is caused by a deposition of urate crystals from the blood in joints and soft tissues, followed by inflammation Typically affects the joint at the base of the great toe Can usually be controlled with diet: drugs, plenty of water, less red meat, avoidance of alcohol More common in men In untreated gouty arthritis, the bone ends fuse

Joints (Articulations) Functions of joints Classifying Joints: Functional or Structural Naming Movements of Bones Around Joints Types of Joints Based on Movement Selected Key Joints: Shoulder, Elbow, Hip, Knee Joint Injuries Chronic Joint Conditions: Arthritis