Joints

Question 1

what are joints?

Answer 1

where bones come together so articulations allow movements and holds skeleton together

Question 2

how are joints classified? explain

Answer 2

function - how moveable the joint is; structure- how surfaces are connected

Question 3

describe three functional classifications

Answer 3

synarthroses- immovable
amphiarthroses- slightly moveable
diarthroses- freely moveable

Question 4

describe synarthroses with an example

Answer 4

strong union between bones so they are important in protecting organs e.g. skull

Question 5

describe amphiarthroses with an example

Answer 5

thick fibre cartilaginous discs e.g. vertebral discs

Question 6

describe diarthroses with an example

Answer 6

wide range of motion e.g. elbow

Question 7

what are the three types of diarthroses

Answer 7

uniaxial- movement in one plane around single axis; biaxial- two; multiaxial; three

Question 8

describe three classifications of structure

Answer 8

fibrous joints= immovable ; synovial joints= freely moveable ; cartilaginous = range of motion

Question 9

what do fibrous joints contain and where would they be found

Answer 9

contain lots of dense connective tissue and no joint cavity; found at connecting bones that don’t require movement

Question 10

describe structure of fibrous joints

Answer 10

• bone edges serrated and united by layer of fibrous tissue
• periosteum layer is continuous

Question 11

what are the two types of fibrous joints? give examples

Answer 11

• syndesmoses; bones are connected only by ligaments, united by fibrous tissue or internal interaction membrane e.g. fibula and tibia
• gomphoses; peg- in socket that occurs between a tooth and its alveolar socket as teeth are embedded

Question 12

what ligament holds the teeth in place

Answer 12

periodontal

Question 13

describe a cartilaginous joint

Answer 13

joints connected by cartilage so lack joint cavity

Question 14

what are the two types of cartilaginous joints ?Give examples

Answer 14

• synchondroses - contain hyaline cartilage so bones are united, present at epithelial growth plates, between first rib and manubrium of sternum
• symphyses contain fibrocartilage so is incompressible = shock absorber e.g. found between vertebrae and in pelvis

Question 15

what is a synovial joint

Answer 15

freely movable joint with a cavity filled with fluid to allow mobility i.e. found in limbs

Question 16

what covers opposing bones and why?

Answer 16

articular cartilage to protect the ends of bones; allows the bones to move against one another

Question 17

what is contained within joint cavity? what does it contain?

Answer 17

synovial fluid- very viscous, contains hyaluronic acid secreted by cells in membrane

Question 18

what is the point of the synovial fluid?

Answer 18

acts as lubricant so reduces friction between cartilage layers

Question 19

what does the synovial membrane together with fibrous layer compromise

Answer 19

articular capsule; reinforces ligaments, nerves and vessels

Question 20

where does fibrous joint capsule attach?

Answer 20

away from articular margins; strengthened by ligaments and muscles that cross the joint

Question 21

what do some synovial joints have?

Answer 21

fatty pads or discs of fibrocartilage separating the articulating surfaces= menisci in knee

Question 22

how is some movement possible?

Answer 22

gliding/ twisting of one bone against another

Question 23

what are the seven types of synovial joints

Answer 23

hinge, pivot, ball and socket, ellipsoid, saddle, condyloid

Question 24

what is a hinge joint? give an example

Answer 24

allows movement in one axis; supported by string collateral ligament e.g. elbow

Question 25

what is a pivot joint? give an example

Answer 25

allows rotation at one long axis; one bone rotates around another with fibrous ring e.g. radius- ulnar joint

Question 25

what is pronation and supination?

Answer 25

pronation= base of radius rotates over and around head of ulna
supination= palms face up

Question 26

what is ball and socket? give an example

Answer 26

ball of one joint fits into socket of another so movement in all axes and at least three planes e.g. hip

Question 27

what is ellipsoid? give an example

Answer 27

• similar to ball and socket; ligaments/ oval shape prevent rotation so only rotates two axes e.g. radiocarpal

Question 28

what is a saddle joint? give an example

Answer 28

• similar to ball and socket but limited rotation as both bones have concave and convex surfaces e.g. carpometacarpal joint

Question 29

what is condyloid? give an example

Answer 29

• modified ball and socket; active movement in two axes and passive in third e.g. wrist

Question 30

describe closely packed joints

Answer 30

stable joints that are strongly united so little movement; associated with protection and weightbearing

Question 31

describe less closely packed joints

Answer 31

less stable as allows more range of motion e.g. shoulder

Question 32

what is joint arthrokinematics

Answer 32

specific movements of joint surfaces

Question 33

what do complex movements involve

Answer 33

roll, spin and glide; never work in isolation