Articulations

which of the follow describes a hinge joint correctly a. the convex articular surface of one bone fits into a concave articular surface of another bone b. one bone rotates around another bone c. the flat articular surfaces of two bones glide past one another d. the rounded, ball like end of one bone fits into a concave depression of another bone

a.

your friend is on the basketball court when she is pushed over the leg of a fallen paler and lands on the court on her bent knee. She tries to get up but immediately realizes something is wrong. The trainer examines her knee and finds excessive motion with the posterior drawer test. what has happened?

an injury to the posterior cruciate ligament of PCL. this ligament functions to stop the tibia from sliding backward on the femur. If the test resulting in excessive motion it would indicate an injury to the PCL occurred because it is no longer able to hold the tibia in place

synovial joints are surrounded. by a/an __________________ and filled with _________________ a. articular disc; serous fluid b. joint capsule; synovial fluid c. articular cartilage' serous fluid d. articular disc' synovial fluid

b

the main function of a fibrous joint is to a. allow motion to occur between two bones b. provide stability between two bones c. unite two bones with cartilage d. allow some motion while still providing stability between two bones e. unite two bones with a synovial cavity

b

which of the following correctly describes a pivot joint a. the convex articular surface of one bone fits into a concave articular surface of another bone b. one bone rotates around another bone c. the flat articular surfaces of two bones glide past one another d. the rounded, ball like end of one bone fits into a concave depression of another bone

b

what are multiracial joints

ball and socket joints they move around all three axis

what are biaxial joints

condyloid and saddle they move around two axis

an amphiarthrosis is defined as a a. joint that allows no motion b. joint that is freely moveable c. joint with multiple axes of motion d. joint that allows some motion

d

true or false articular discs provide a smooth, nearly frictionless surface for articulation

false

true or false bursae improve the fit between two bones in a synovial joint

false

true or false fluid filled sacs called ligaments often lie between tendons and the joint capsule of a synovial joint

false

true or false the tendon sheath of a synovial joint is lined with a synovial membrane

false

example of where circumduction and rotation can occur

glenohumeral joint

example of where rotation but not circumduction can occur

head and neck

what are uniaxial joints

hinge, pivot they are joints that move around one axis

what is circumduction

is the circular movement of a limb - moving a limb such as an arm in circles

in the condition synovitis the synovial membrane secretes excess synovial fluid. How might this affect the function of the synovial joint?

it would cause an increased level of fluid which would cause swelling which would restrict the joints movements and or the numbers of axis its able to cross

what are non axial joints

joints that do not move around an axis

could a fibrous joint perform its functions if it were a diarthrosis

no, because it functions to stabilize the area between bones. it could not be classified as this which is a freely moving joint) because then it would not provide support or stabilization

which class of synovial joint do you think would be the most stable and which would be the least stable

plant joints because they allow motion in a gliding motion rather than around an axis and a synovial joint is weak because it moves around all three axis

how would the function of synovial joints be changes if they lacked joint cavities

there would be not frictionless movement, which means that movement would be harder and possibly more painful

when the shoulder joint dislocates, it most commonly dislocates posteriorly, meaning that the joint capsule tears on the posterior side and the head of the humorous pushes partly out through the capsule. Why do you think the posterior capsule more commonly tears?

this is when the humerus is pushed back behind the glenoid. This occurs because there are not the light ligaments (shape and strength wise) needed to keep the joint in place

true or false the articulating ends of the bones in a synovial joint are covered by articular cartilage

true

what is rotation

turning a limb around an axis - like moving the head from facing in one direction to the other

example of where circumduction but not rotation can occur

wrist - radoiocarpal joint