Transcript Bones Part 4 Joints

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
Syndesmoses
2.
•
interosseous membrane
Gomphoses
3.
•
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
Symphyses
2.
•
•
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 CO2 & O2 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 medially @
intertarsal joints (soles face each other)
 eversion: movement of soles laterally @
intertarsal 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
 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