<p> Lecture 8: Articulations (Joints)</p><p>I. Classification by Function</p><p>A. synarthroses - immoveable (sutures in cranium)</p><p>B. amphiarthroses - slightly moveable (tibia-fibula)</p><p>C. diarthroses - freely moveable (shoulder joint)</p><p>II. Fibrous Joints</p><p>A. Sutures</p><p>1. between cranial bones 2. very tight, thin layer of connective tissue 3. synostoses - bone replaces connective in adult</p><p>B. Syndesmoses</p><p>1. very little freedom for movement 2. interosseous membrane/ligament present</p><p>C. Gomphoses</p><p>1. one part fit tightly into the other 2. periodontal tissue holds parts firmly together 3. example: teeth in the mandible and maxillae</p><p>III. Cartilaginous Joints</p><p>A. Synchondrosis</p><p>1. hyaline cartilage --> bone over time 2. example: area between epiphysis & diaphysis of bone 3. example: joint between ribs and sternum</p><p>B. Symphysis</p><p>1. bones connected by disc of fibrocartilage 2. allows for slight movement (amphiarthrotic) 3. example: pubic symphysis, intervertebral discs</p><p>IV. Synovial Joints</p><p>A. Structure</p><p>1. any joint where there is a space between bones 1 2. synovial cavity - space between the bones 3. freely moveable joints (diarthrotic) 4. articular cartilage - covers articular surface 5. articular capsule - encloses the cavity itself a. fibrous capsule - attached to periosteum i. ligaments - clearly defined connections b. synovial membrane - inner layer of capsule i. produces synovial fluid ii. reduces friction in the joint 6. accessory ligaments - additional support a. extracapsular - outside capsule b. intracapsular - within capsule 7. articular discs (menisci) - pads between bones 8. bursae - sac-like structures that reduce friction a. between tendons, muscle, ligaments: and bone</p><p>B. Factors that Limit Movement in a Joint</p><p>1. "fit" between the articulating bones 2. tension of the ligaments 3. arrangement and tension of the muscles 4. opposition of muscles restricting range of motion</p><p>C. Types of Movements in the Joint</p><p>1. gliding - one bone slides over another (carpals) 2. angular motion - change the angle between bones a. flexion - decrease the angle b. extension - increase the angle c. abduction - away from the midline d. adduction - toward the midline 3. rotation - circular motion of the long axis 4. circumduction - distal end moves in a circle 5. inversion - sole of foot moves medially 6. eversion - sole of the foot moves laterally 7. dorsiflexion - raising foot toward lower limb 8. plantar flexion - extending foot away from lower limb 9. protraction - forward in the horizontal plane 10. retraction - backward in the horizontal plane 11. pronation - radius "radiates" over the ulna 12. supination - forearm returns to anatomical position 13. elevation - upward motion, in a superior direction 14. depression - downward motion, inferior direction</p><p>D. Types of Synovial Joints</p><p>1. gliding joints (arthrodia) (nonaxial) a. side-to-side; back-and forth in grinding manner b. carpals, tarsals, scapula-clavicle 2 2. hinge joints (ginglymus) (monaxial) a. movement occurs in a single plane b. elbow, ankle, interphalangeal 3. pivot joints (trochoid) (monaxial) a. rotation around another bone b. atlas-axis (C1-C2), proximal radius-ulna 4. ellipsoidal joints (condyloid) (biaxial) a. side-to side; back-and-forth in smooth manner b. radius-carpal joint in the wrist 5. saddle joints (sellaris) (biaxial) a. one bone "sits" in the saddle of another b. trapezium-thumb metacarpal joint 6. ball-and-socket joints (spheroid) (triaxial) a. works just like a joy-stick in all directions b. humero-scapular joint; coxal (hip) joint</p><p>V. Examples of Major Articulations (Joints)</p><p>A. Humeroscapular Joint (Shoulder)</p><p>1. head of humerus <--> glenoid cavity of scapula 2. ball-and-socket joint 3. articular capsule - surrounds entire joint 4. coracohumeral ligament 5. glenohumeral ligaments 6. transverse humeral ligament 7. glenoid labrum - fibrocartilage around glenoid fossa 8. bursae of the shoulder a. subscapular, deltoid, acromial, coracoid</p><p>B. Femorocoxal Joint (Hip)</p><p>1. head of femur <--> acetabulum of coxal bone 2. ball-and-socket joint 3. articular capsule -surrounds entire joint 4. iliofemoral ligament 5. pubofemoral ligament 6. ischiofemoral ligament 7. capitate ligament - acetabulum --> head of femur 8. acetabular ligament - fibrocartilage around acetab. 9. transverse ligament of acetabulum </p><p>C. Tibiofemoral Joint (Knee)</p><p>1. Three Joints in One a. patellofemoral joint b. medial tibiofemoral joint c. lateral tibiofibular joint 2. articular capsule 3 3. ligaments: patellar, oblique popliteal, arcuate popliteal, tibial collateral, fibular collateral 4. intraarticular ligaments a. anterior cruciate ligaments b. posterior cruciate ligaments 5. articular discs a. medial meniscus b. lateral meniscus 6. bursae: anterior, medial, lateral</p><p>4</p>