15.2 Anatomy: Joints of the upper limb

Question 1

What are the 4 features of a synovial joint?

Answer 1

Articular cartilage (avascular, aneural)
Fibrous capsule
Intrinsic/extrinsic ligamnets
Synovial membrane (lines all non-articular surfaces)

Question 2

What is a labrum?

Answer 2

A fibrocartilagenous rim, deepens socket in ‘ball and socket joints’

Question 3

What is special about fat pads?

Answer 3

Intra-articular but extrasynovial

Question 4

What is the blood/nerve supply of discs/menisci?

Answer 4

Shock absorption, blood/nerve supply to outer third

Question 5

What may bursae do?

Answer 5

Communicate with the joint cavity (sometimes synovial joint)

Question 6

What are 3 features of stable joints?

Answer 6

Congruent (deep) articular surfaces
Tight capsule, strong ligaments
Limited ROM

Question 7

What are 2 features of mobile joints?

Answer 7

• Stability dependent on short fixator/stabiliser muscles

- Susceptible to subluxation or dislocation

Question 8

Where does the head of the humerus articulate?

Answer 8

WIth the Glenoid fossa (scapula)

Question 9

What are the 2 processes above the Glenoid fossa?

Answer 9

Acromion and coracoid (medially)

Question 10

What are the 2 ligments that attach to the clavicle?

Answer 10

Medial: costoclavicular
Lateral: coracoclavicular (stabilises)

Question 11

What is the ratio between the movement of the scapula on the chest wall?

Answer 11

2:1 shoulder joint to scapular movement

Question 12

Clavicle fracture:
Where does fracture occur?
Which direction does each break go?

Answer 12

Lat 1/3rd–>med 2/3rd

Lateral down, medial up

Question 13

What does a disc increase?

Answer 13

The complexity of movement on each side

Question 14

What type of joint is the sterno-clavicular? What reinforces it?

Answer 14

Intra-articular disc, strong capsule (very stable)

Costoclavicular (accessory) ligament limits movement

Question 15

When can sternoclavicular subluxation occur? What can be impinged?

Answer 15

Motor vehicle accident, chest hits steering wheel.

Subclavian vessels (vein and artery) located directly behind

Question 16

What type of joint is the acromioclavicular joint? What is it stabilised by?

Answer 16

Plane synovial joint (weak capsule), main stabiliser: coracoclavicular ligament

Question 17

What are the different grades of acromioclavicular subluxation?

Answer 17

Grade 1: AC stretched
Grade 2: AC torn, disrupted
Grade 3: AC ruptured (joint separation)

Question 18

What is a feature typical of a long bone?

Answer 18

Epiphyses at either end (also where muscles attach, traction)

Question 19

Where are 3 sites susceptible to injury on the humerus?

Answer 19

Surgical neck (elderly, axillary nerve susceptible)
Mid shaft (radial nerve)
Supracondylar (median nerve and brachial artery endangered)

Question 20

What are the 5 layers of the shoulder joint?

Answer 20

Layer 1: articular surfaces (unstable)
Layer 2: labrum and attachments (deepened)
Layer 3: capsule (loose, ROM in 3 planes)
Layer 4: muscles (rotator cuff)
Layer 5: coracoacromial ligament and bursa

Question 21

Where are the deficiencies in the shoulder capsule?

Answer 21

Anteriorly:
long head of biceps
bursa (subscapular)

Question 22

What is a frozen shoulder?

Answer 22

Also known as adhesive capsulitis:
Capsule contracts (esp. if stationary for a long time, elderly etc.), decreased ROM

Question 23

What muscles comprise the rotator cuff?

Answer 23

Teres minor, supraspinatus, infraspinatus and subscapularis

-(can act as prime movers but mainly stabilisers)

Question 24

What can happen with a weak rotator cuff?

Answer 24

Humerus can slide upwards with pull of deltoid, ‘impingement’ of supraspinatus

Question 25

What can occur if there is instability at the coracoacromial ligament and bursa?

Answer 25

Bursa can become impinged between bone and ligament (shoulder abduction esp. w/ weak RC)

Question 26

What is the most common dislocation of the shoulder?

Answer 26

Anterior/inferior-force applied to abducted and externally rotated arm

(Post. less common, electric shock or epileptic fit)

Question 27

What structure can be endangered by inferior dislocation of the shoulder?

Answer 27

Axillary nerve (supplying the deltoid and overlying skin)

Question 28

What does the painful arc of movement refer to?

Answer 28

Shoulder painful in 60-120 degree abducted movement