Joints of Shoulder Complex

Question 1

What are the key features of a synovial joint?

Answer 1

articular cartilage, fibrous capsule, ligaments, synovial membrane

Question 2

What is the key feature of articular cartilage?

Answer 2

it is avascular and aneural

Question 3

What will a tear in a synovial membrane cause?

Answer 3

haemarthrosis

Question 4

Why dont ligaments repair quickly?

Answer 4

because they have a poor blood supply

Question 5

When do most bones of the skeleton commence ossification?

Answer 5

in utero at 8 weeks

Question 6

What does a fracture at the surgical neck of the humerus endanger?

Answer 6

the axillary nerve

Question 7

What does a mid-shaft fracture of the humerus endanger?

Answer 7

the radial nerve

Question 8

What does a supracondylar fracture of the humerus endanger?

Answer 8

median nerve and brachial artery

Question 9

Where is the clavicle likely to fracture?

Answer 9

between the lateral 1/3rd and the medial 2/3rds - lateral part will be pulled down and the medial part will be pulled up

Question 10

What is the scapulothoracic joint?

Answer 10

a pseudo joint between the scapula and the thoracic wall - sliding movement

Question 11

What movements occur at the sternoclavicular joint?

Answer 11

elevation and depression and rotation about the longitudinal axis

Question 12

What is the main limitation to movement at the sternoclavicular joint?

Answer 12

the costoclvicular extrinsic ligament - keeps the medial end of the clavicle down

Question 13

What structure is endangered by subluxation of the sternoclavicular joint?

Answer 13

subclavian artery and vein

Question 14

In what plane are the surfaces of the acromioclavicular joint?

Answer 14

the sagittal plane

Question 15

What prevents upward displacement of the clavicle at the AC joint?

Answer 15

the coracoclavicular ligament

Question 16

What causes subluxation of the AC joint?

Answer 16

anteroposterior force on the shoulder

Question 17

What is the key feature of the glenohumeral joint?

Answer 17

it is incongruent - a large humeral head fitting into a small shallow glenoid fossa

Question 18

What tendon has attachment to the glenoid labrum?

Answer 18

long head of biceps

Question 19

Where does the capsule of the shoulder join?

Answer 19

at the anatomical neck above and the surgical neck below

Question 20

What are the two deficiencies in the capsule of the glenohumeral joint?

Answer 20

for the long head of biceps and for the subscapular bursa

Question 21

What is frozen shoulder?

Answer 21

when the capsule contracts - due to trauma, diabetes etc. - restricts movement

Question 22

What are the muscles of the rotator cuff?

Answer 22

supraspinatus, infraspinatus, teres minor, subscapularis

Question 23

Where to the tendons of the muscles of the rotator cuff insert?

Answer 23

blend with the capsule

Question 24

If the rotator cuff is weak and the humerus slides upward due to the pull of deltoid, what structure may be entrapped?

Answer 24

supraspinatus

Question 25

What will cause subacromial bursitis?

Answer 25

abduction movement - especially if rotator cuff is weak

Question 26

Does the subacromial bursa communicate with the joint capsule?

Answer 26

no

Question 27

In what direction is dislocation of the shoulder caused by force applied to the end of the limb?

Answer 27

dislocates anteriorly and the head of the humerus will then drop inferiorly due to the capsule being weakest inferiorly

Question 28

What direction is dislocation of the shoulder caused by an electric shock?

Answer 28

posterior

Question 29

What structures are endangered by shoulder dislocation?

Answer 29

axillary nerve

Question 30

How do you assess whether the axillary nerve is damaged?

Answer 30

pin prick in the military badge area