Shoulder Flashcards
What is the primary function of the scapula?
Keep glenoid fossa and acromion in proper position during movement of humerus
Subscapularis
What does it do?
Where does it attach?
Internal rotation. Also depresses / centers humeral head in glenoid as deltoid abducts the arm.
Attaches to lesser tuberosity
What is the most commonly injured rotator cuff muscle?
Subscapularis
Infraspinatus / teres minor
What doe they do?
Where do they attach?
External rotation
Attach to greater tuberosity
What does supraspinatus do?
Abduction in plane of scapula (scaption)
Shoulder separation Which joint? Cause Epidemiology Treatment
- 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.
Gender distribution for GH dislocation
3x more common in males
Mechanism of GH dislocation
Forced external rotation and abduction.
What nerve is commonly damaged w/ GH dislocation? What does it innervate?
Axillary nerve innervates deltoid
Bankart lesion
Damage to anterior / inferior labrum, which provides lots of stability, so damage → high rate of recurrence
Hill-Sachs lesion
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.
What causes a posterior GH dislocation?
Trauma, electrical shock, or seizure
Position of arm after posterior GH dislocation
Adducted and internally rotated
How is posterior GH dislocation diagnosed?
Axillary X ray
Treating GH dislocations
- 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.
What 2 things may subacromial bursitis cause?
Impingement or RC dysfunction
Causes of impingement syndrome (7)
Overuse, aging, hypermobility, acromial hooking, spurring, calcification of coracoacromial ligament, supraspinatus dysfunction (humeral head rises w/ abduction).
3 intrinsic causes of RC tendonopathy
Poor microvascular blood supply, apoptosis, tissue overload / overuse
2 extrinsic causes of RC tendonopathy
External compression of cuff and scapular dyskinesis
Treating impingement and RC tendonopathy in young vs old.
- 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
Treating RC tears
- 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.
What x ray views are used for shoulder dislocations?
Scapular Y view or axillary view
