joints

Question 1

3 main categories of joints

Answer 1

fibrous, cartilaginous, synovial

Question 2

3 types of fibrous joints

Answer 2

suture, syndesmosis, gomphosis

Question 3

fibrous joints

Answer 3

held together by fibrous connective tissue, little movement

short, direct and often transitory

no joint cavity

Question 4

suture joints (fibrous joint)

Answer 4

• flat bones of skull
• little movement but allow for growth
• close to form synostosis: fusion or 2 or more bones of skull

Question 5

bregma

Answer 5

• meeting of sagittal and coronal suture on top of head (hole on head)
• also known as fontanelle
• persists in toy breeds; hole never closes up

Question 6

syndesmosis joints (fibrous joint)

Answer 6

• intervening tissue; two adjacent bones linked together for example tibia and fibula
• more movement than suture but very restricted

Question 7

gomphosis (fibrous joint)

Answer 7

• peg in a socket joint
• usually teeth
• firm attachment
• very slight movement

Question 8

cartilaginous joints formed from

Answer 8

cartilage, fibro-cartilage or both
- no joint capsule

Question 9

2 types of cartilaginous joints

Answer 9

• symphysis (fibrocartilaginous)
• synchondrosis (hyaline cartilage)

Question 10

cartilaginous joints movement

Answer 10

limited; compression or stretching

Question 11

symphysis (cartilaginous joint)

Answer 11

• fibrocartilaginous
• fibre sandwich between two layers of cartilage
• ex where 2 os coxae come together
• ex intervertebral disc

Question 12

intervertebral disc joints

Answer 12

• in between vertebrae, fibres arranged in circular fashion like an onion, annulus fibrosum
• in the middle of disk is nucleus pulposus which is a gelatinous material
• slipped disk is rupture of annulus and nucleus pulposus spits out; puts pressure on spinal cord

Question 13

synchondrosis joint (cartilaginous)

Answer 13

• hyaline cartilage
• mainly transitory joints in growing bones
• ex is epiphyseal cartilage aka growth plate
• ex is costochondral joint (rib to sternum)
• ex hyoid to skull

Question 14

synovial joints all have

Answer 14

• joint capsule
• joint cavity
• synovial fluid (fills joint cavity)
• articular cartilage

Question 15

classification of joints (simple and compound)

Answer 15

• simple: 2 articular surfaces
• compound; more than 2

Question 16

ball and socket joint

Answer 16

enarthrosis
ex hip and shoulder

Question 17

hinge joint

Answer 17

(ginglymus)
flex and extends, no lateral movement

Question 18

condylar joint

Answer 18

ex stifle
condyles on condyles
flex and extend, no lateral movement
looks unstable, requires ligaments

Question 19

pivot joint

Answer 19

trochoid
ex atlanto-axial
get rotation around a long axis

Question 20

gliding joint

Answer 20

arthrodial
anything that doesn’t fit into above categories
ex is carpometacarpals joints

Question 21

outer layer of joint capsule

Answer 21

stratum fibrosum

Question 22

inner layer of joint capsule

what does it do

Answer 22

• stratum synoviale
• loose connective tissue; very thin, only 2-3 cells thick
• phagocytic: cells will engulf any tissue/ rubbish in synoviale fluid and removed
• cells also secrete things such as hyaluronan which gives synoviale fluid is viscous sticky character

Question 23

stratum fibrosum (outer layer of joint capsule) + stratum synoviale (inner layer of joint capsule) =

Answer 23

synovial membrane

Question 24

synovial membrane is

Answer 24

• secretory
• also absorptive (keeps right amount of synovial fluid in the joint) aided by movement –> lack of movement in old people = swollen joints bc too much synovial fluid
• other characteristics include folds, pouches and fat pads

Question 25

articular cartilage is usually composed of

Answer 25

hyaline cartilage but fibrocartilage in temporo-mandibular joint

Question 26

function of articular cartilage

Answer 26

reduce friction and shock absorption avascular and no nerves

Question 27

articular cartilage get nutrition from

Answer 27

synovial membrane and some from underlying bone

Question 28

how is articular cartilage regenerated

Answer 28

multiplication of healthy cartilage cells and by conversion of stratum synoviale cells best regeneration at periphery because nearer nutrients from synovial membrane

Question 29

thickness of cartilage depends on

Answer 29

weight bourne on it so thickest in middle articular surface

Question 30

surface of articular cartilage we see

Answer 30

- collagen fibres anchored in underlying bone - hoops form a corrugated surface - springy for shock absorption and resist shear forces

Question 31

synovial fluid functions and what does it contain

Answer 31

- contains mucopolysaccharides (hyaluronan) --> viscous fluid - functions are nutrition of articular cartilage, lubrication and shock absorption

Question 32

ligaments are

Answer 32

usually thickenings of stratum fibrosum in response to tensional forces

Question 33

ligaments function

Answer 33

strengthen joints, restrain movement, aided by tendons and extrinsic ligament

Question 34

ligaments made up of

Answer 34

almost pure collagen

Question 35

difference between tendons and ligaments

Answer 35

ligaments are NOT associated with muscle, tendons are

Question 36

some ligaments that are remnants of

Answer 36

tendons

Question 37

true or false ; some ligaments hardly restrain movement

Answer 37

true

Question 38

menisci

Answer 38

special fibrocartilage articular structures

Question 39

where are menisci found

Answer 39

stifle and temporo-mandibular joints only

Question 40

menisci function

Answer 40

shock absorbers, may also increase 'fit' or SA joint

Question 41

what do menisci have which is atypical for cartilage

Answer 41

a nerve supply

Question 42

dislocation/ luxation of joints is prevented by

Answer 42

- shape or articualr surfaces - ligaments - muscles or tendons - cohesive force (= surface tension) of synovial fluid

Question 43

flexion

Answer 43

reduce angle of joint

Question 44

extension

Answer 44

increase angle of joint

Question 45

overextension

Answer 45

extend over 180 degrees

Question 46

gliding

Answer 46

rubbing between joints

Question 47

abduction

Answer 47

move away from midline

Question 48

adduction

Answer 48

move toward midline

Question 49

circumduction

Answer 49

large circular movement of limb

Question 50

bursae

Answer 50

- not a joint - synovial structures - reduce friction between tendons and bones

Question 51

when synovial bursa wrap all the way around tendons they are called

Answer 51

tendon sheath

Question 52

tendon sheaths are held in place by tissue called

Answer 52

retinaculum

Question 53

sesamoid bones

Answer 53

small gliding bones associated with tendons where tendons run over synovial joints

Question 54

sesamoid bone functions

Answer 54

reduce fiction and maintain alignment +/- increase leverage