Chapter 8 joints Flashcards
exam 2 prep
what are the functions of joints
mobility : allow movement of body parts
- diff types of joints allow for diff amount and type of movement
- joints vary in shape
stability : hold the skeleton together
- joints hold bones in place : prevent bones coming apart
- prevent damage to internal structures
classification of joints
can either be structural or functional
Structural : type of tissue that connects bones at articulating surface
FIBROUS , CARTILAGINOUS OR SYNOVIAL
Functional : amount of movement allowed by joint
synarthroses : no movement
amphiarthroses : limited movement
diarthroses : freely moveable
where would you not want diarthrotic joints?
axial skeleton
protective qualities of axial skeleton - do not want movement
fibrous joints
structural
joints composed of collagen fibers of connective tissue
no joint cavity
movement : synarthroses , few amphiarthroses
short collagen fibers dont allow large degree of movement
types of fibrous joints
Sutures
syndesmoses
gomphoses
sutures
fibrous joint
short and strong bands of collagen fibers seen between the bones of the skull
little movement permitted
syndesmoses
fibrous joint
bones are connected to one another by ligaments (bands of fibrous tissue that join bone to bone)
MOVEMENT ALLOWED BY JOINT DEPENDS ON LEGTH OF LIGAMENT BANDS (LONGER = MORE MOVEMENT)
gomphoses
fibrous joint
only joint that doesnt join bone to bone
jones tooth to bony alveolar socket
TEETH ARE NOT BONES
- peridontal ligament : joins mandible/ maxilla to tooth
fibers are short : limited movement
fontanelles
soft spots in fetal skull
allows for movement of skull bones due to rapid brain growth and and allows for squezzing of head through pelvic girdle
Cartilaginous joints
bones joined by cartilage
no joint cavity
synarthroses or amphiarthroses
synchondroses
type of cartilaginous joint
bones united w a plate of hyaline cartilage
SYNARTHROSES
ex ; epiphyseal plate and costal cartilage
symphyses
cartilaginous joint
fibrocartilage joins bone
some movement but limited
FIBROCARTILAGE ABSORBS SHOCK
bounces back after movement
highly compressible and resilient
what is an example of a symphyses
intervertebral joints : prevent vertebrae from touching
discs can herniate : fibrocartilaget bulges out and presses on nerve
PAINFUL
synovial joints
joint cavity
diarthroses
almost all in appendicular skeleton : limbs need to move
structures found in synovial joints
articular cartilage
joint cavuty
articular capsule
synovial fluid
reinforcing ligaments
innervation and vascularization
Articular cartilage
-hyaline cartilage covering bone ends
-wraps around epiphysis and prevents bones from directly rubbing against each other
joint cavity
small space between articulaing bones
almost nonexisitent - very small/flat
synovial fluid found here
Articular capsule
two layered capsule that encloses joint cavity
fibrous layer : outer layer that is continuous w periosteum - prevents two articulated bones from being pulled apart (STRONG/STABLE)
synovial membrane : inner layer that lines joint cavity
produces synovial fluid and is not found in places where there is articular cartilage
synovial fluid
slippery fluid occupying space in joint capsule
joint not active : fluid viscous and is soaked up by articular cartilage
joint active : fluid watery and is found in joint cavity
watery consistency allows articular carilage to slide against one another and prevent it from wearing down
how is synovial fluid released from articular cartilage when joint becomed active
when weight is applied to joint - articular cartilage will push together and squeeze synovial fluid out
reinforcing ligaments
band like ligaments that join articulating bones
stabilize joint
innervation and vascularization
innervation : joints supplied w sensory nerve fibers
- lets yk position of joint , stretch of tissue , pain : warning sys.
vasculartization : rich blood supply to joints
provide raw materials for synovial fluid formation
Factors influencing joint stablity
articular surfaces
ligaments
muscle tone
articular surfaces
better two bones fit together - more difficult to pull out
doesnt play a huge role in joint stability
ligaments
the more ligaments the stronger the joint
if ligament is too stretched out - lowers joint stability DISLOCATION
ligaments only work well when they have other structures backing them up
muscle tone
tendons attach muscle to bone and often wrap around joints
braces joints and holds it in place
MOST IMPORTANT FOR STABILITY
movements allowed by synovial joints
nonaxial
uniaxial
biaxial
multiaxial
non axial movement
no axis around which movement can take place
bones that articulate have flat surfaces
GLIDING - slide pass each other
plane joint - cube shaped bones
uniaxial movement
allows for movement of joint around a single axis
flexion/extension OR rotation
hinge joint - flexion/extension
pivot joint - rotation
biaxial movement
allows for movement of joint around 2 axis
flexion/extension and abduction/adduction
condylar and saddle joint
multiaxial movement
allows for movement around multiple axes
flexion/extension , abduction/adduction AND rotation
if all movements done together = CIRCUMDUCTION
ball and socket joint
temporomandibular joint
biaxial hinge joint
articular disc divides synovial cavity into superior and inferior parts
superior : lateral excursion - wiggle jaw left to right
inferior : elevation/depression - chewing (raise/lower jaw)
glenohumeral joint
humerus articulates w the scapula
most freely moving joint in the body
structures that provide increased stability for glenohumeral joint
. Reinforcing ligaments
- coracohumeral ligament : (1) back of shoulder
- glenohumeral ligament : may have 0 but max of 3 - front (anterior) of shoulder
. rotator cuff
- 4 muscles and tendons encircle the joint
- wrap around joint : brace joint
extreme circumduction can injure rotator cuff
. Glenoid Labrum
- rim of fibrocartilage around glenoid fossa - deepen socket of joint so they fit better
elbow joint
humerus articulates w ulna
hinge joint
close fit of trochlea and trochlear notch : hard to pull apart
muscle and tendon of arm muscle wrap around elbow to provide stability
ulnar collateral ligament : medial side
radial collateral ligament : lateral side
BOTH PREVENT LATERAL MOVEMENT
coxal joint
head of femur articulates w os coxa
strong ligaments and articular surfaces
Illiofemoral ligament
pubofemoral ligament
ischiofemoral ligament
all 3 wrap and twist around joint
joint in use twist 3 ligaments tigheter
acetabular labrum
ring of cartilage around acetabulum to further deepen socket - head of femur fits better PREVENT DISLOCATION
knee joint
single joint cavity shared by 3 seperate joints
menisci
thin layer of fibrous cartilage at outer margins of tibiofemoral joints
function on menisci
part of knee joint
slightly deepen socket
cartilage absorbs shock - and prevents damage to bone tissue
femur easily detaches from the tibia - moves in opposite directions
extracapsular and capsular ligament
part of the knee joint
prevent hyperextension of knee
intracapsular ligaments (cruciate ligaments)
secure articulating bones , prevent displacement
anterior cruciate ligament
intracapsular ligament
prevents forward sliding of the tibia - prevents hyperextension of the knee
smaller than PCL - attaches to the front of the tibia
more easily damaged: especially when changing directions
posterior cruciate ligament
prevents backward sliding of the tibia and foward sliding of femur
attaches to posterior portion of tibia
Arthritis
can be inflammatory or degenerative
inflammatory - tissue in joint inflamed, filled w fluid
degenerative - joint tissue being destroyed
Acute or chronic
most widespread crippling disease in N.A
acute arthritis
bacterial, inflammatory
easily treated w antibiotics
bacterial infection in the joint - becomes inflamed - give antibiotics to kill bacteria
chronic arthritis
inflammatory/ degenerative
long-lasting (months/yrs)
tends to be progressive: pain gets worse , limited mobility
osteoarthritis
most common form of chronic arthritis
progresses slowly and is irreversible
inflammatory - takes yrs to feel pain and is difficult to treat
what increases risk of osteoarthritis
60+ female
joint is overused/underused
genetic : family w OA
trauma : repeated dislocation
cause of osteoarthritis
articular cartilage destroyed faster than replaced
broken cartilage never replaced
effect of osteoarthritis
exposed bone rubs together causing bone spurs
bone spurs - abnormal bone formation: bone trying to protect itself
no empty space between bones
bone becomes deformed and restricts the movement of the joint
Rheumatoid Arthritis
autoimmune chronic inflammatory disorder
immune system is attacking bone tissue
incurable
see symptoms at ab 30-40 yrs old
increased risk for RA
females : stronger immune system
genetic
features of RA
bilateral and degenrative
bilateral - seen on both sides of the body
seen mostly on fingers , wrists, ankles and feet
flair ups and periods of remission
flair ups - pain/swelling remission - no pain/swelling
remission is temporary
as RA progresses, remission becomes shorter, and flare-ups worsen
progression of RA
synovial mem inflamed
lymphocytes/macrophages flood the area to destroy inflammation - also destroy synovial men.
break down of synovial mem causes accumulation of synovial fluid that solidifies - pannus forms
breaks down cartilage tissue which is replaced by scar tissue
ankylosis - scan tissue is turned into bone : lock bone together
COMPLETE LOSS OF MOBILITY
helping RA
no cure
prescribe sterioids - slow down the immune sys. - slow down the degeneration of joints
pain meds
replace joint w artifical joint before ankylosis occurs
