Topic 3: BONES, JOINTS AND MUSCLES OF THE ELBOW REGION

Question 1

Classification of the elbow joint

Answer 1

Synovial, uniaxial, hinge

Question 2

Movements of the elbow joint

Answer 2

Flexion, extension

- transverse axis (sagittal plane)

Question 3

Fat pad in the olecranon fossa functions

Answer 3

sits in the fossa to absorb shock when the elbow is extended.
- comes out in extension, in in flexion (check that)

Question 4

Articular surfaces of the elbow joint

Answer 4

1. head of radius - articulates with capitulum of humerus

2. trochlear notch of ulna - articulates with trochlear of humerus

Question 5

Elbow joint complex

Superior RU joint classification

Answer 5

synovial, uniaxial, pivot (radius pivots around the ulna)

Question 6

Elbow joint complex

Superior RU joint movements

Answer 6

Pronation & supination

- longitudinal axis (trans plane)

Question 7

Superior RU joint articular surfaces

Answer 7

1. head of radius

2. radial notch of ulna

Question 8

Elbow and superior RU joints articular capsule

Answer 8

common capsule for elbow and superior RU joint

Question 9

Elbow and superior RU joints articular capsule attachments

Answer 9

1. attaches at articular margins of humerus
2. attaches to articular margins of radius
3. no direct attachment to ulna

Question 10

Where is the elbow and superior RU joint articular capsule thickest?

Answer 10

thickest & strongest at sides of joints, relatively weak anteriorly, weak posteriorly

Question 11

Elbow and superior RU joints synovial membrane

Answer 11

common to both joints

Question 12

Elbow and superior RU joints extrasynovial fat pads

Answer 12

occupy the fossae where the bony projections do not (absorb shock when elbow = extended)

Question 13

Elbow and superior RU joints Ligaments

Annular ligament shape

Answer 13

“ring-shaped” or circular

Question 14

Annular ligament attachments

Answer 14

both attachments on ulna (radial head can spin)

Question 15

Annular ligament surrounds what>

Answer 15

head of the radius

Question 16

Annular ligament stops:

Answer 16

ulna moving laterally (prevents breaking of the 2 bones)

because; when annular ligament = put under tension, brings ulna closer into the superior RU jt

Question 17

Annular ligament movements

Answer 17

allows pronation/ supination

Question 18

Annular ligament shape/ where is it wider and why?

Answer 18

wider superiorly than inferiorly, funnel shaped –> stops radius from slipping out inferiorly
- follows shape of radial head –> not cone shaped in kids; can easily inferiorly dislocate

Question 19

Ligaments of the elbow and superior RU joints

Answer 19

1. medial/ ulnar collateral ligament

2. lateral/ radial collateral ligament

Question 20

Where is the joint capsule stronger in the elbow joint & why is that so?

Answer 20

stronger & thicker on sides
- thin anteriorly & posteriorly so that you can facilitate movements in the sagittal plane
- dont want to do elbow abduction/ adduction –> joint capsule prevents these movements
(ligaments (collateral) make the jt capsule thicker & stronger on the sides which = prevents movements)

Question 21

Mechanical functions of ligaments

Answer 21

to limit &prevent movements

Question 22

Elbow and superior RU joints

Collateral ligaments function

Answer 22

tense throughout flexion/ extension range

Question 23

Ulnar collateral ligament of the elbow function

Answer 23

3 parts

- PREVENTS abduction

Question 24

Radial collateral ligament of the elbow function

Answer 24

2 parts

- PREVENTS ADDUCTION

Question 25

where do the 2 slips of the radial collateral ligament (elbow) go to?

Answer 25

- 1 slip goes to annular ligament on the radius | - 1 slip goes to ulna

Question 26

Classification of the inferior radioulnar joint

Answer 26

synovial, uniaxial, pivot

Question 27

Movements of the inferior radioulnar joint

Answer 27

``` - pronation - supination longitudinal axis (transverse plane) ```

Question 28

Intermediate radioulnar joint classification

Answer 28

fibrous, syndesmosis (interosseous membrane)

Question 29

Which direction do the fibres of the intermediate radioulnar joint pass?

Answer 29

downward from radius to ulna --> radial head would shatter with FOOSH if no interosseous membrane (distributes the forces between the two bones as the radial head is a lot smaller than the ulnar head and would easily break)

Question 30

Function of the interosseous membrane of the intermediate RU joint

Answer 30

- enables distribution of force/ shock to prevent radial head break or dislocation of the sternoclavicular joint - dissipates force as go towards axial skeleton --> SC jt dislocation prvenets

Question 31

Direction of forces in the intermediate RU jt

Answer 31

from radius--> ulna --> humerus --> shoulder girdle --> axial skeleton

Question 32

Other function of Interosseous membrane

Answer 32

+ oblique cord; acts as a fulcrum for pronation- supination & attachment site for muscles

Question 33

FUNCTIONAL ANATOMY OF THE ELBOW REGION | What is the movement between the radius & ulna at the superior RU joint during pronation & supination?

Answer 33

spin of radial head on radial notch of ulna (radial head fits into radial notch of ulna) - radial tuberosity turns inwards

Question 34

FUNCTIONAL ANATOMY OF THE ELBOW REGION | What is the movement between the radius & ulna at the inferior RU joint during pronation & supination?

Answer 34

2 ways: 1. pronation WITH translation 2. pronation WITHOUT translation

Question 35

Pronation WITH translation

Answer 35

roll and slide of ulnar notch of radius on ulnar head - 5th digit (pinky) is the axis of rotation - radius = translating over the ulna

Question 36

Pronation WITHOUT translation

Answer 36

slight extension & abduction of ulna (by the anconeus) to move it out of the way of the radius so that radius can roll over easily - middle finger = axis of rotation - ulna gets out of the way so that the radius can roll over it nicely

Question 37

Spurt

Answer 37

mover

Question 38

Shunt

Answer 38

stabiliser

Question 39

Rotary component definition

Answer 39

force of a muscle contributing to a bones movement around a jt/ axis

Question 40

Transarticular component role

Answer 40

pulls bone towards joint

Question 41

Shape of rotary vs transarticular graph for a spurt (force)

Answer 41

rotary >> transarticular | - muscles have a functional role to produce force

Question 42

Shape of rotary vs transarticular graph for a Shunt (stabilise)

Answer 42

transarticular >> rotary - PA = closer to fulcrum & DA = further from the fulcrum of the joint - primary role of muscle is to get a bone into a joint & stabilise it

Question 43

Implications for recruitment

Answer 43

1. where speed and load = low -- use a mover muscle | 2. where speed and/ or load are increased - use a mover muscle and recruit a stabiliser muscle to increase jt stability

Question 44

What do you recruit when speed & load = low?

Answer 44

mover muscle

Question 45

What do you recruit when speed and/ or load = increased?

Answer 45

use a mover muscle and recruit a stabiliser muscle to increase jt stability - also think about synergists

Question 46

Golden rules for muscle recruitment

Answer 46

1. Recruit a monokinetic muscle first (want less effort/ energy expenditure) 2. recruit polykinetic muscles as the need for increased force increases 3. recruit synergists as required 4. recruit stabiliser (shunt) muscles as load and/ or speed increase for stability

Question 47

Monokinetic definition

Answer 47

One movement, one jt

Question 48

Polykinetic definition

Answer 48

multiple movements; maybe multiple jts