Honors Anatomy & Physiology

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

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

 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

 Articulating bones held very closely together by fibrous CT  3 types: 1. Sutures skull bones 2. Syndesmoses interosseous membrane 3. Gomphoses dentoalveolar joint

 allows little or no movement  bones are tightly connected by either hyaline cartilage or fibrocartilage  2 types: 1. Synchondoses hyaline cartilage connects bones epiphyseal plate 2. Symphyses fibrocartilage connects bone pubic symphysis

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

 secreted by synovial membrane  viscous, clear, pale yellow fluid  forms film over surfaces w/in articular capsule  functions: 1. reduce friction 2. absorbing shocks 3. supporting chondrocytes in w/in articular cartilage

 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 CO 2 & O 2 out of blood vessels in synovial membrane  form bubbles in synovial fluid  bubbles pop

 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

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

 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

 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

 1. Gliding  relatively flat surfaces move back-and-forth & side-to-side

 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

 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

 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)

 5. protraction/retraction  protraction: movement of part of body anteriorly in transverse plane  retraction: returning a protracted part of body to anatomical position

 6. inversion/ eversion  inversion: movement of soles intertarsal joints (soles face each other)  eversion: movement of soles intertarsal joints

 7. dorsiflexion/ plantar flexion  dorsiflexion: bending ankle in direction of dorsum (superior surface)  plantar flexion: bending ankle in direction of plantar surface

 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

 9. opposition  movement of thumb in which thumb moves across palm to touch tips of the fingers on same hand

 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

 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

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