articulation Flashcards
what is a joint (articulation)
a point where two bones meet whether or not it is movable
what is the only joint where bone isnt joining bone
teeth –> gomphosis joint, periodontal ligaments
what holds joints together
skeletal muscle and connective tissue
tendons and ligaments
cartilage
ex. fibrocartilage discs joining bone of vertebrae
pubic symphasis joining pubi
what are the many functions of joints
- supporting and binding
ex. PCL, ACL, MCL, LCL in the knee keep it together - movement
shape changing during childbirth
movement in response to muscle contraction - bone growth
growth of bones occur at joints
epiphyseal plate – a joint between bone adn bone that is connected with hyaline cartilage
becomes a bony joint (epiphyseal line)
what are fontanels
softer and unfused bones of the skull in infants
not all attached to each other
immobile
they are growing and fusing together
so that they can overlap and make childbirth a little easier
what are synovial joints
the most moveable joints
most likely to be diseased or injured
ex. glenohumeral joint
gleno = glenoid cavity
humeral = humerus
ex. tibiofemoral joint
tibia and femur
ex. atlandtooccipital joint
atlas and occipital condyles
what is the articular cartilage of joints
hyaline cartilage on opposing bone surface
spongy cushion absorbs compression
<1 mm
prevents bone-bone contact (that is bad can lead to osteoarthritis D:)
the cavities in the cartilage (like a sponge) act as a cushion
what is the joint cavity of joints
cavity surrounding the whole joint which possesses a small amount of synovial fluid
unique to synovial joints
what is synovial fluid
a viscous, slippery fluid which occupies the joint cavity
its a weight bearing film that reduces friction
important to the normal health of joints
articular cartilage lacks a blood supply, but the joint cavity is highly vascularized and brings nutrients and takes wastes from the cartilage
the synovial fluid interacts with the articular cartilage to exchange these materials
why should you warm up before exercising?
warming up your joints reduces the viscosity of the synovial fluid, making it easier for it to permeate the cartilage and bring nutrients and take wastes
it is like you are saturating the sponge of cartilage to make it bigger and more cushiony
people with osteoporosis (or other joint troubles) need PT to help repair their joints
this increases the movement of fluid through the joint so that it can heal
what is the joint capsule
encloses the joint cavity and is made up of:
- synovial membrane
deeper
loose connective tissue
has synovial cells which produce the synovial fluid - fibrous capsule
more superficial
dense irregular connective tissue
continuous with the articulating bones (in contact with the periosteum of bone)
what are the reinforcing ligaments in joints
ligaments that provide strength to the joint
typically have individual names (ex. medial collateral ligament MCL)
holds the entire joint capsule and the two bones together
ligaments stretch and do not recoil – if it is loose, it will stay loose
double jointed poeple –> their reinforcing ligaments are looser than in most people, allowing for no pain when doing funky things with joints
compressing the joint cavity –> popping the air bubbles of the synovial fluid
what are the menisci of joints and their functions
a fibrocartilage pad in between articulating bones
partially divide the joint cavity into left or right sections
functions:
- asborb shock and pressure
- guide bones and improve fit
- increase stability of joint
kind of like a half moon shape
why are knee injuries involving cartilage and ligaments problematic
they are not very vascularized and therefore cannot obtain nutrients/waste exchange from blood
its dependent on synovial fluid which is very slow
what is the point of arthroscopic surgery
makes it relatively easy to repair tears in cartilage or ligaments without being too invasive
