Joints. Articulations Arthroses

Transcription

1 Joints Articulations Arthroses 1

2 Joints, defined Points of contact between Two bones Bone and teeth Joint classification: 2 schemes Functional classification degree of movement permitted Structural classification Anatomical organization type of binding material 2

3 Functional Classification Based on degree of movement 3 categories Synarthroses (singular is synarthrosis) Amphiarthroses (singular is amphiarthrosis) Diarthroses (singular is diarthrosis) Synarthroses immovable joints Strong 4 types Sutures Gomphoses Synchondroses Synostoses 3

4 Sutures dense fibrous connective tissue Example: cranial sutures Gomphoses fibrous connective tissue (periodontal ligament) Example: teeth and sockets (alveoli) 4

5 Synchondroses hyaline cartilage Examples: Epiphyseal cartilages R1 and manubrium Synostoses IS Fused bones Examples: L and R frontals fuse to a single frontal bone Epiphyseal line 5

6 Amphiarthroses Bones united by cartilage or collagen fibers Strong Slightly movable 2 types Syndesmoses Symphyses Syndesmoses Fibrous connective tissue organized into bundles or sheets Examples: distal tibiofibular joint interosseous membranes 6

7 Symphyses Bones are attached by fibrocartilage Examples: pubic symphysis intervertebral discs Diarthroses: Synovial joints Most joints Freely movable Components Articular capsule Articular cavity Articular cartilage Synovial membrane 7

8 articular (joint) capsule Like a finger trap articular (joint) capsule Encloses the space where two bones come together Composed of dense connective tissue 8

9 articular (joint) capsule Encloses the space (synovial cavity) where two bones come together Composed of dense connective tissue articular cartilage composed of hyaline cartilage provides a smooth surface for movement provides a little shock absorption 9

10 joint cavity (synovial cavity) Space inside articular capsule Lined by synovial membrane Produces synovial fluid Filled with synovial fluid from: Membranes in Chapter 4 Synovial Fluid consists of interstitial fluid plus proteoglycans honey-like when joint is immobile, movement thins it; becomes watery use of joint causes increased production of synovial fluid Functions of synovial fluid lubrication of joint shock absorption nutrient distribution 10

11 Joint Accessories, they re hip! Cartilages and fat pads Ligaments Tendons Bursae Cartilages Menisci (s. mensicus) also called articular discs pads of fibrocartilage stabilize joints by improving the fit 11

12 Fat pads covered by synovial membrane protection of joint and bones packing material of joints Ligaments and tendons confer stability to joints Ligaments support, strengthen, and reinforce joints some make up articular capsule Tendons limit range of motion of joints 12

13 Bursae and Tendon Sheaths Filled with synovial fluid, lined by synovial membrane Bursae, pl (singular is bursa) (defined = pouch) between bone and skin, tendons, ligaments, or muscles Tendon Sheaths Tube-like bursae Factors stabilizing synovial joints joint capsule other ligaments shape of articulating surfaces menisci tension in associated muscles and tendons 13

14 Joint injuries Sprain Dislocation Nerve supply (innervation) Nerve endings supply articular cartilage ligaments Information relayed regarding pain degree of movement 14

15 Blood supply all joint components excepting articular cartilage nutrient/waste exchange is via synovial fluid pumping action discussed earlier Movements at Synovial Joints Linear motion /gliding Angular Circumduction Rotation 15

16 Movements at Synovial Joints Linear motion /gliding Tarsals Carpals Movements at Synovial Joints Angular motion Flexion Decrease joint angle Extension Increase joint angle Hyperextension Increase beyond anatomical position Abduction Away from body Adduction Toward body 16

17 Movements at Synovial Joints Rotation Multiple types Supination Pronation Medial rotation Lateral rotation Movements at Synovial Joints FYI only * useful for lab Others Circumduction Inversion Eversion Dorsiflexion Plantar flexion Opposition Protraction Retraction Elevation Depression 17

18 Types of Synovial joints FYI only Gliding joints Hinge joints Pivot joints Ellipsoid joint Saddle joint Ball-and-socket joint No test questions from 9-4 intervertebral articulations 9-5 shoulder and elbow 9-6 hip and knee 18

19 Arthritis: inflammation of synovial joints; impairs joint mobility Result of damage to articular cartilage Cause of damage varies Many types Pain, stiffness, swelling Osteoarthritis Degenerative joint disease Most common Causes Cumulative wear and tear Genetic factors with collagen formation Rheumatoid arthritis 19

20 Rheumatoid Arthritis Inflammatory condition Autoimmune disease of synovial membrane Possible causes allergies bacterial viral infections genetic factors Gouty Arthritis Uric acid crystals form in synovial fluid Accumulation interferes with function Common site: 1 st metacarpal-phalangeal joint 20

21 Gout: a metabolic disorder of handling nitrogenous waste Protein catabolism results in hydrocarbon chains + amino groups (NH 2 ) forms of nitrogenous waste: NH 2 in solution à Ammonia (NH 3+ ) in fish NH 3+ + CO 2 à Urea in mammals (you J) & amphibians Urea concentrated à Uric acid in reptiles & birds Effects of Aging on Joints d production of synovial fluid articular cartilage thins with age loss of flexibility in ligaments, due to less use wear and tear and genetic factors may exacerbate these aging effects Note: Disuse causes d amount of synovial fluid, d flexibility of ligaments/tendons, muscular atrophy leads to less use 21

22 Using your joints Hyaline cartilage lacks direct circulation Acute use and training effects Both increase the thickness of cartilage Because cartilage absorbs synovial fluid 15% increase in thickness w/in 15 minutes Benefits: 1 increase of exchange 2 increases contact area, decreases chance of injury Read section 9-8 Contains nice summarizing comments 22