Shoulder

Question 1

What is the primary function of the scapula?

Answer 1

Keep glenoid fossa and acromion in proper position during movement of humerus

Question 2

Subscapularis
What does it do?
Where does it attach?

Answer 2

Internal rotation. Also depresses / centers humeral head in glenoid as deltoid abducts the arm.
Attaches to lesser tuberosity

Question 3

What is the most commonly injured rotator cuff muscle?

Answer 3

Subscapularis

Question 4

Infraspinatus / teres minor
What doe they do?
Where do they attach?

Answer 4

External rotation

Attach to greater tuberosity

Question 5

What does supraspinatus do?

Answer 5

Abduction in plane of scapula (scaption)

Question 6

Shoulder separation
Which joint?
Cause
Epidemiology
Treatment

Answer 6

• AC joint sprain
• Usually caused by a direct fall on the lateral shoulder.
• 5x more common in males. Usually 3rd decade.
• Type I / II don’t need surgery. Use sling, ice, pain meds, and rehab.
• III is controversial. IV-VI often require surgery.

Question 7

Gender distribution for GH dislocation

Answer 7

3x more common in males

Question 8

Mechanism of GH dislocation

Answer 8

Forced external rotation and abduction.

Question 9

What nerve is commonly damaged w/ GH dislocation? What does it innervate?

Answer 9

Axillary nerve innervates deltoid

Question 10

Bankart lesion

Answer 10

Damage to anterior / inferior labrum, which provides lots of stability, so damage → high rate of recurrence

Question 11

Hill-Sachs lesion

Answer 11

Indentation of humeral head caused by impaction of posterior superior humeral head on anterior inferior glenoid as it pops out of the socket. Also cause high rate of recurrence.

Question 12

What causes a posterior GH dislocation?

Answer 12

Trauma, electrical shock, or seizure

Question 13

Position of arm after posterior GH dislocation

Answer 13

Adducted and internally rotated

Question 14

How is posterior GH dislocation diagnosed?

Answer 14

Axillary X ray

Question 15

Treating GH dislocations

Answer 15

• Reduce dislocation after careful neurologic exam. Do post-reduction x rays to evaluate for fractures.
• Sling / PT
• Follow-up exam 3-10 days after dislocation. Include neurovascular exam, ROM, strength, and stability tests.
• PT is mainstay for chronic instability. Surgery if this fails.
• Pxs w/ Bankart lesions should have surgery right away due to 90% chance of repeat dislocations w/o surgery.

Question 16

What 2 things may subacromial bursitis cause?

Answer 16

Impingement or RC dysfunction

Question 17

Causes of impingement syndrome (7)

Answer 17

Overuse, aging, hypermobility, acromial hooking, spurring, calcification of coracoacromial ligament, supraspinatus dysfunction (humeral head rises w/ abduction).

Question 18

3 intrinsic causes of RC tendonopathy

Answer 18

Poor microvascular blood supply, apoptosis, tissue overload / overuse

Question 19

2 extrinsic causes of RC tendonopathy

Answer 19

External compression of cuff and scapular dyskinesis

Question 20

Treating impingement and RC tendonopathy in young vs old.

Answer 20

• Address causative factors:
• Younger population – instability, muscle weakness or flexibility, overuse, capsular or muscle imbalance
• Older population –impingement secondary to bone spurs or degenerative tendon
• Use PT first for both populations

Question 21

Treating RC tears

Answer 21

• Surgery for young / active pxs or acute large tears
• Non-operative for chronic or partial tear. Includes PT and steroid injections.
• Not all are fixed b/c often don’t cause problems. Partial / full thickness tears are found in half of asymptomatic 50 year olds and 80% of asymptomatic 80 year olds.

Question 22

What x ray views are used for shoulder dislocations?

Answer 22

Scapular Y view or axillary view