Honors Anatomy to be copied Skeletal System 4 Honors Anatomy to be copied

Joints & Homeostasis Joints contribute to homeostasis by holding bones together in ways that allow movement & flexibility

Joints aka: “articulation” or “arthrosis” a point of contact between 2 bones, a bone & cartilage, or between a bone & tooth

Joint Classification 1. structural classification based on anatomical characteristics Fibrous joints Cartilagenous joints Synovial joints 2. functional classification based on type of movement they permit Synarthrosis Amphiarthrosis Diarthrosis

Fibrous Joints Articulating bones held very closely together by fibrous CT 3 types: Sutures skull bones Syndesmoses interosseous membrane Gomphoses dentoalveolar joint

Gomphoses

Cartilagenous Joints allows little or no movement bones are tightly connected by either hyaline cartilage or fibrocartilage 2 types: Synchondoses hyaline cartilage connects bones epiphyseal plate Symphyses fibrocartilage connects bone pubic symphysis

Symphyses

Synovial Joints distinguishing characteristics: synovial joint cavity filled with synovial fluid bones covered by articular cartilage reduces friction

Synovial Fluid secreted by synovial membrane viscous, clear, pale yellow fluid forms film over surfaces w/in articular capsule functions: reduce friction absorbing shocks supporting chondrocytes in w/in articular cartilage

By the way…. cracking sounds heard as joints move or popping sounds people make when the “crack” their knuckles explanation: When synovial cavity expands  creates partial vacuum  suction from that draws CO2 & O2 out of blood vessels in synovial membrane  form bubbles in synovial fluid  bubbles pop

Sprains a forcible wrenching or twisting of a joint that stretches or tears ligaments but does not dislocate the bones occurs when ligaments are stressed beyond their capacity may have associated damage to surrounding blood vessels, muscles, tendons, or nerves

Strains stretched or partially torn muscle often due to muscle contracting suddenly & powerfully

Bursae saclike structures situated to alleviate friction in some joints filled with fluid similar to synovial fluid located between: skin & bones tendons & bones muscles & bones ligaments & bones

Bursitis inflammation of a bursa usually caused by irritation from repeated, excessive exertion of a joint or by: trauma, infection (syphilis or TB), RA symptoms: pain, swelling, tenderness, limited movement

Types of Movements @ Synovial Joints 1. Gliding relatively flat surfaces move back-and-forth & side-to-side

Types of Movements @ Synovial Joints 2. flexion/extension/ hyperextension: opposite movements flexion: decrease in angle between articulating bones extension: increase in angle between articulating bones hyperextension: continuation of extension beyond the anatomical position

Types of Movements @ Synovial Joints 3. abduction/adduction/ circumduction abduction: movement of bone away from midline adduction: movement of bone toward midline circumduction: movement of distal end of a body part in a circle

Types of Movements @ Synovial Joints 4. elevation/depression: elevation: upward movement of part of body (closing mouth, shrugging shoulders) depression: downward movement of part of body (opening mouth, returning elevated shrugged shoulders to anatomical position)

Types of Movements @ Synovial Joints 5. protraction/retraction protraction: movement of part of body anteriorly in transverse plane retraction: returning a protracted part of body to anatomical position

Types of Movements @ Synovial Joints 6. inversion/ eversion inversion: movement of soles medially @ intertarsal joints (soles face each other) eversion: movement of soles laterally @ intertarsal joints

Types of Movements @ Synovial Joints 7. dorsiflexion/ plantar flexion dorsiflexion: bending foot @ ankle in direction of dorsum (superior surface) plantar flexion: bending foot @ ankle in direction of plantar surface

Types of Movements @ Synovial Joints 8. supination/pronation supination: movement of forearm in which palm is turned anteriorly pronation: movement of forearm in which distal end of radius crosses over distal end ulna & palm is turned posteriorly

Types of Movements @ Synovial Joints 9. opposition movement of thumb in which thumb moves across palm to touch tips of the fingers on same hand

Ball - & - Socket Joint ball-like surface of one bone fits into a cuplike depression of another bone permits movement around 3 axis + all directions in between flexion extension abduction adduction circumduction rotation

Homeostatic Imbalances Rheumatoid Arthritis (RA) autoimmune disease: immune system attacks joint linings characterized by: inflammation of joint  swelling, pain, loss of function usually bilateral joints involved but may not be to same degree

Medical Terminology arthralgia: pain in a joint subluxation: partial or incomplete dislocation of a joint