119 Shoulder trauma

Question 1

What is this?

Answer 1

Hill-Sach’s lesion - when the posterior part of the humeral head hits the glenoid head during dislocation causing a cortical depression #

Question 2

What is an apprehension test in Msk?

Answer 2

Placing the humeral head in a position of imminent subluxation or dislocation which makes the pt recognise the familiar pattern of instability and react with anticipated fear.

Question 3

What is classed as a recurrent dislocation?

Answer 3

>3 dislocations

Question 4

Which nerve supplies the biceps brachii, coracobrachialis and brachialis?

Answer 4

Musculocutaneous

Question 5

What area is of skin is supplied by the axillary nerve?

Answer 5

Regimental badge area

Question 6

What is the clinical presentation of damage to the ulnar nerve?

Answer 6

Ulnar claw

Question 7

What is the risk of dislocation of the SC joint in a posterior direction?

Answer 7

Damage to the big vessels posterior to the joint

Question 8

What runs in the bicipital groove?

Answer 8

Long head of biceps tendon

Question 9

Which ligament is the strongest?

• AC
• coracoclavicular

Answer 9

Coracoclavicular

Question 10

What is the direction of the humeral head during an anterior dislocation?

Answer 10

Antero-inferior

Question 11

What is a Bankart lesion?

Answer 11

Labral tear from the glenoid

Question 12

Which muscle is weakened following damage to the axillary nerve?

Which muscle compensates in this situation?

Answer 12

• deltoid
• trapezius compensates

Question 13

What is a prefixed brachial plexus?

Answer 13

Contribution of anterior ramus of C4

Question 14

What does a lesion to the upper parts of the brachial plexus cause?

Answer 14

Erb’s palsy

Question 15

What does a lesion to the lower parts of the brachial plexus cause?

Answer 15

Klemperer palsy - results in ulnar claw

Question 16

What can deposits of pyrophosphate from tendons cause if they’re shed into the subachromial bursa?

Answer 16

Bursitis with severe pain and shoulder restriction

Question 17

• What is adhesive capsulitis?
• When can it develop?

Answer 17

• Frozen shoulder
• Following
  
  • rotator cuff injuries
  • hemiplagia
  • chest/breast surgery
  • MI

Question 18

What are the differences between young and mature cartilage?

Answer 18

• young:
  
  • abundent in cells
  • low ECM
  • no tide mark
  • no zonal morphology

Question 19

What does the the tidemark in articular cartilage restrict?

Answer 19

Chondrocytes access to nutrients from the vasculature of the subchondral bone

Question 20

Where does cartilage get its nutrients from?

Answer 20

Synovial fluids from synovial capsule vessels

Question 21

What are the changes which happen in articular cartilage with ageing?

(5 listes)

Answer 21

1. cell metabolism slows and number decreases
2. collagen matrix proteins cross-link
3. reduction in type IX collagen
4. biochemical changes in aggrecan
5. degradation products decrease

Question 22

What is formed by the modification of hydroxyl using residues in the collagen chains?

Answer 22

Pyridinoline cross-links in mature cartilage

Question 23

What is the role of transglutaminases in mature cartilage?

Answer 23

Enzymatically cross-link martix proteins (between lysine and glutamine)

Question 24

What are the changes to chondroitin sulphate in ageing cartilage?

Answer 24

They become shorter

Question 25

What changes happen to the keratan sulphate as cartilage ages?

Answer 25

Increases in size

Question 26

Name 2 types of matrix proteinases

Answer 26

* ADAMTS * metalloproteinases

Question 27

Which 2 minerals are required for MMPs and ADAMTS?

Answer 27

Zinc and/or calcium

Question 28

What are the 4 types of MMPs in cartilage metabolism?

Answer 28

1. collagenases 2. gelatinases 3. stromelysins 4. membrane bound MMPs

Question 29

What are the 2 principal matrix proteinases for aggrecan metabolism?

Answer 29

* ADAMTS4 * ADAMTS5

Question 30

Why does articular cartilage lack a perchondrium?

Answer 30

Perichondrium contains bvs and nerves - cartilage needs to remain avascular and aneural to be able to function in resisting compressive loads - would occlude vbs.

Question 31

What is the classic first sign of OA in cartilage?

Answer 31

Surface fissures in the articular cartilage + chondrocyte clustering

Question 32

What is the territorial matrix in hyaline cartilage?

Answer 32

The matrix immediately surrounding the cells

Question 33

What is the name of the cavity in which the chondrocytes lie?

Answer 33

Lacunae

Question 34

Where can elastic cartilage be found?

Answer 34

Epiglottis External ear External auditory canal

Question 35

Apart from IVD, where else is fibrocartilage found?

Answer 35

Ligament/tendon entheses + anywhere tendon presses against bone

Question 36

What is synovium?

Answer 36

* Thin membrane in synovial joints which lines the joint capsule * 1-3 layers of macrophage and fibroblast-like cells which produce the synovial fluid

Question 37

What are Benninghoff arcades?

Answer 37

Collagen fibre organisation in articular cartilage

Question 38

What makes up the 'wet' weight of articular cartilage? (5 listed)

Answer 38

* 70% water * 20% collagens * 7% PGs * 2% cells * 1% other proteins

Question 39

What makes up the 'dry' weight of articular cartilage?

Answer 39

* 75% collagens * 22% PGs * 3% other proteins

Question 40

What type of collagen is type IX? Function?

Answer 40

FACIT collagen - binds to type II collagen and is important in organisating fibrils

Question 41

What is the function of the N globular domain in type IX collagen?

Answer 41

Anchors type II to the other matrix components

Question 42

Where else in the body does type IX and type II interact?

Answer 42

* Cornea * vitreous humour of the eye

Question 43

Where is type VI collagen found?

Answer 43

In pericellular matrix - forms hine fibrils in lacunae and around cells

Question 44

What is collagen type XI involved with?

Answer 44

Fibril nucleation

Question 45

Name 3 small leucine rich PGs

Answer 45

* decorin * biglycan * fibromodulin

Question 46

Which chemical groups link GAGs to protein cores in cartilage? (2)

Answer 46

* Hydroxyl groups of serine/threonine * Amine groups of asparagine

Question 47

Which groups on the GAGs provide them with polyanionin properties?

Answer 47

* carboxyl * sulphate

Question 48

What is the role of biglycan and where is it found?

Answer 48

* Small leucine rich PG * found in per-cellular regions * binds GFs near cell surface receptors

Question 49

What are canaliculi?

Answer 49

Canals which house long cell processes of the osteocytes which communicate via gap junctions

Question 50

What lies in the spaces between the trabeculae?

Answer 50

Bone marrow

Question 51

What are trabeculae composed of?

Answer 51

Lamallae of bone with lacunae containing osteocytes

Question 52

From which type of cell are osteocytes derived from?

Answer 52

Osteoblasts

Question 53

Which cell type is responsible for resorbing bone?

Answer 53

Osteoclasts

Question 54

What is osteoid?

Answer 54

Uncalcified matrix in developing spongy bone

Question 55

What is a Howship's lacuna? How is it formed?

Answer 55

* Lacuna in which the osteoclast lies * result of bone erosion activity of the osteoclast