Shoulder

Question 1

What is the main cause of RTC injuries in patients under 40yo?

What imaging is gold standard?

Answer 1

trauma injuries

MRI

Question 2

What does the shoulder girdle consist of?

Answer 2

clavicle, scapula and humerus

Question 3

What does 1/3 of the humeral head sit in that gives the joint its mobility?

Answer 3

the glenoid fossa

Question 4

What are the RTC muscles?
Where do 3/4 of these muscles originate and insert?

Answer 4

supraspinatus, infraspinatus, teres minor, subscapularis

originates on posterior scapula, inserts on greater tubercle of humeral head (except subscap)

Question 5

Why is the supraspinatus the most frequently injured shoulder tendon?

Answer 5

because it runs under the AC joint and under the humeral head (creates friction and pinch points)

Question 6

The teres minor tendon almost never fails, but why would the muscle be evaluated?

Answer 6

the muscle can be scanned in comparison to the infra to look for evidence of long standing tears

Question 7

How many muscles and tendons does the subscap have?

Answer 7

4 muscles and 4-6 tendons that insert on the lesser tuberosity of the humeral head

Question 8

Which head of the biceps cannot be evaluated and why?
Which head is evaluated on every scan and where is it seen?

Answer 8

short head: inserts on coracoid process and isn’t seen

long head: sits in bicipital groove and inserts on the superior glenoid labrum

Question 9

What is the RTC interval? why is it important to evaluate this area?

Answer 9

separation of subscap by supra by the biceps tendon

can be used to differentiate between pathology of the supra from the subscap

Question 10

What is the glenoid labrum?

Answer 10

fibrocartilaginous ring lining outer glenoid fossa
- deepens the socket, posterior glenoid labrum is evaluated for fluid

Question 11

What is another potential space for fluid accumulation in a supra tear?

Answer 11

AC joint

Question 12

What are bursae?

What is the main bursa in the shoulder (largest in body)?

Answer 12

small thin sacs that contain small amounts of synovial fluid to reduce friction where tendons and muscles cross joint capsules

subacromial-subdeltoid bursa (essentially 2 but evaluated as 1)

Question 13

What age will patients typically experience RTC failure?
which fail first etc?

Answer 13

over 40yo, incidence increases with age and can be asymptomatic (often incidental findings)

supra, then infra and subscap when the original tear extends

Question 14

What causes acute tears?

Answer 14

trauma, falls, ruptures or dislocations

Question 15

What causes chronic tears?

Answer 15

occur as a cumulative progression of an injury from overhead activities that cause microtraumas due to impingement

Question 16

Where do partial thickness tears typically begin?

Answer 16

usually in the critical zone: found in anterolateral supra tendon, 1cm from insertion on greater tuberosity

may involve articular surface (most common) or bursal surface (2nd)

Question 17

How does a partial thickness tear appear?

Answer 17

anechoic defect in tendon fibers (acute)
or hyperechoic area due to blood and bursal granulation tissue within the frayed tendon (chronic)

Question 18

What are secondary indicators of partial thickness tears?

Answer 18

diffuse thickening and bone irregularities

Question 19

Explain the difference in articular surface tears and bursal surface tears

(appearance and symptom)

Answer 19

1- typically presents as fluid in the biceps tendon sheath
2- tender to palpation

Question 20

What is a complete tear?

Answer 20

involving full thickness and full width

retraction occurs with a separation of 2-4cm between torn tendon ends

Question 21

What do full thickness tears demonstrate that partial tears dont?

Answer 21

communication between glenohumeral joint and subacromial bursa, leads to a large amount of fluid in SASD bursa

Question 22

List the most common to rare tendon tears in the shoulder

Answer 22

supra, infra, subscap, teres

Question 23

What are some signs that indicate a full thickness tear?

Answer 23

cartilage interface sign: echogenic line on anterior surface of humeral head cartilage
naked tuberosity sign: deltoid muscle in direct contain with humeral head
double effusion sign: fluid in SASD bursa and biceps tendon sheath

also deltoid muscle or SASD bursa herniation into RTC

Question 24

Explain calcific tendinosis

Answer 24

process that can affect any RTC tendons
calcium aggregates can be solid, paste or liquid

Question 25

What happens when calcium bursts out of the tendon into the SASD bursa?

what can be seen in painful calcs?

Answer 25

acute and painful synovitis

increased CD signals

Question 26

What is subluxation of biceps tendon?

Answer 26

dislocation outside of the bicipital groove
due to a problem with the transverse humeral ligament that holds the tendon in place, abnormally shallow bicipital grooves or subscap tears

Question 27

What is the most common site for subluxation of the biceps tendon?

What is the sonographic appearance?

Answer 27

medical and deep to the subscap

empty groove, possibly filled with granulations and fibrous tissue and seeing the biceps tendon over the lesser tuberosity
tendon sheath may be filled with fluid

Question 28

What is subacromial impingement syndrome?

Answer 28

lateral shoulder pain that occurs during elevation of the arm above 180*

defined as compression of the RTC and/or SASD bursa by the overlying coraco-acromial arch

Question 29

What can cause subacromial impingement syndrome?

Answer 29

can be caused by osteophytes on the acromion, SASD bursitis or RTC tear