joints

Question 1

what is a joint

Answer 1

union between 2 or more rigid components (bone or cartilage)

also known as articulation

Question 2

why do we need joints

Answer 2

movement and growth

Question 3

what are the 3 types of joints

Answer 3

fibrous
cartilaginous
synovial

Question 4

fibrous joints

Answer 4

dense fibrous connective tissue - collagen fibres hold the bones together
high tensile strength
little movement in adults

Question 5

examples of fibrous joints

Answer 5

periodontal ligament
cranial sutures
interosseous membranes

Question 6

types of cartilaginous joints

Answer 6

1y: synchondroses
2y: symphyses

Question 7

1y cartilaginous joints

Answer 7

allow for bone growth
disappear in adults
no movement - movement can lead to growth plate fractures
made from hyaline cartilage

Question 8

2y cartilaginous joints

Answer 8

don’t ossify with age
found in midline of the body
limited movement
hyaline + fibrocartilage

Question 9

hyaline cartilage

Answer 9

pearly, translucent, fairly elastic and may ossify with age

Question 10

fibrocartilage

Answer 10

fibrous and more resistant than hyaline cartilage

Question 11

synovial joints

Answer 11

greatest movement

may also contain articular discs, ligaments and bursae

Question 12

synovial membrane

Answer 12

produces synovial fluid which lubricates the joint

Question 13

articular cartilage

Answer 13

hyaline cartilage

Question 14

articular discs

Answer 14

firther from the centre of the body

Question 15

ligaments in synovial joints

Answer 15

in and around the joint

can be part of the capsule or outside it

Question 16

6 types of synovial joints

Answer 16

hinge 
saddle 
plane 
pivot 
condylar (ellipsoid)
ball and socket

Question 17

movement at pivot joint

Answer 17

rotational e.g. top of the spine

Question 18

movement at plane joint

Answer 18

sliding and gliding

Question 19

8 joint movements

Answer 19

flexion/extension
abduction/adduction
lateral/medial rotation
circumduction
supi-/pronation
inversion/eversion
dorsi-/plantarflexion
true flexion/extension

Question 20

flexion

Answer 20

two ventral surfaces closer to each other (vice versa for extension)

Question 21

abduction

Answer 21

moving a limb away from the midline

Question 22

adduction

Answer 22

moving a limb towards the body

Question 23

lateral rotation

Answer 23

outwards (bending arm at elbow to 90 degrees then moving forearm away from body)

Question 24

medial rotation

Answer 24

towards the midline

Question 25

circumduction

Answer 25

drawing a circle in the air with whole arm/leg | combination of flexion, extension, abduction and adduction

Question 26

supination

Answer 26

palm facing upwards

Question 27

pronation

Answer 27

palm facing down

Question 28

inversion

Answer 28

moving just the foot towards the midline

Question 29

eversion

Answer 29

moving just the foot away from the midline

Question 30

dorsiflexion

Answer 30

raising the foot upwards towards the shin | flexion

Question 31

plantarflexion

Answer 31

moving the food back away from the shin

Question 32

joint stability

Answer 32

- The more degrees of freedom, the less stable the joint/higher risk if dislocation - Shape of articulating surfaces (e.g. shoulder vs hip, hip is very deep socket and much more stable than the shoulder joint which is easier to dislocate) - Fibrous capsule and ligaments (surround the joint, hold everything in place) Muscles (strong, support the joint), special group of muscles in the shoulder joint which act to support the joint and stabilise it

Question 33

blood supply to the joints

Answer 33

rich blood supply anastomoses (communication between 2 blood vessels w/o an intervening capillary network) - lots of blood vessel branches that reconnect, allows blood an alternative path e.g. during extreme flexion and extension

Question 34

nerve supply to the joints

Answer 34

rich nerve supply - Proprioception (specialised sensory nerve endings that monitor internal changes in the body brought about by movement and muscular activity) - allows sense of the relative position of different parts of the body ○ Proprioceptors not just in muscle spindles but also in joint capsules Hilton's law: the nerve supplying a muscle that crosses a certain joint, also innervates this joint

Question 35

trauma to the joint

Answer 35

(fracture at the joint of the bone, dislocation), close to the joint there is only a thin layer or compact bone (mainly spongy bone)

Question 36

arthritis

Answer 36

(osteo- and rheumatoid) - osteo is the degenerative joint disease, not as simple as wear and tear. Rheumatoid is an autoimmune disease and can also affect other parts of the body.

Question 37

craniosynostosis

Answer 37

(abnormal skill growth due to premature fusion of cranial structures) Sutures in the skull close too early, causes problems in childhood as the brain is still growing and the skull is no longer flexible, leads to deformed skull and can lead to impairments (e.g. can compress nerves)