MSK Shoulder Flashcards
Normal shoulder ROM
Flexion: Extension: Abduction Adduction IR ER
Flexion: 180 Extension: 60 Abduction 180 (120 with thumb pointed down) Adduction: 60 IR: 90 ER: 90
Name the muscles responsible for shoulder flexion 4
- anterior deltoid (axillary nerve from posterior cord C5/6)
- Pec major, clavicular portion (medial and lateral pectoral nerves C5-T1)
- Biceps brachii (musculocutaneous nerve from lateral cord C5/6)
- Coracobrachiolis (musculocutaneous nerve from lateral cord C5/6)
Name the muscles responsible for shoulder extension 5
- posterior deltoid (axillary nerve from posterior cord C5/6)
- Lats dorsi (thoracodorsal nerve from posterior cord C6/7/8)
- Teres Major (lower subscapular nerve from posterior cord C5/6)
- Triceps long head (`radial nerve from posterior cord C6/7/8)
- Pec major (sternocostal portion - medial and lateral pectoral nerves C5-T1)
Name the muscles responsible for shoulder abduction 2
- middle deltoid (axillary nerve from posterior cord C5/6)
2. Supraspinatus (suprascapular nerve from upper trunk C5/6)
Name the muscles responsible for shoulder adduction 7
- pectoralis major (medial and lateral pectoral nerves C5-T1)
- Lat dorsi (thoracodorsal nerve from posterior cord C6/7/8)
- Teres Major (lower subscap n from lateral cordC5/6/7)
- Coracobrachialis (musculocutaneous n from lateral cord C5/6/7)
- Infraspinatus (suprascapular nerve from upper trunk: C5/6)
- Long head of triceps (radial n from posterior cord C6/7/8)
- Anterior and posterior deltoid (axillary nerve from posterior cord C5/6)
Name the muscles responsible for shoulder internal rotation: 5
- Subscapularis (upper and lower subscap nerves from PC C5/6)
- Pectoralis major (medial and lateral pectoral n C5-T1)
- Lats (thoracodorsal n from PC C5/6)
- Anterior deltoid (axillary from PC C5/6)
- Teres major (lower subscap from PC C5/6)
Name the muscles responisble for shoulder external rotation 4
- infraspinatus (suprascapular nerve from upper trunk C5/6)
- Teres Minor (axillary nerve from PC C5/6)
- Deltoid, posterior portion (axillary from PC C5/6)
- Supraspinatus (suprascapular nerve from upper trunk C5/6)
Name the 6 components of the glenohumeral joint
- glenoid fossa
- labrum
- glenohumeral capsule
- glenohumeral ligaments
- dynamic shoulder stabilizers
- Static shoulder stabilizers
describe the balance between the glenohumeral and scapulothoracic joint during arm abduction
There are 2 degrees of glenohumeral motion for every 1 degree of scapulothoracic motion during arm abduction (120 glenohumeral and 60 scapulothoracic motion)
Scapulothoracic motion allows the glenoid to _____ and permits glenohumeral ____ without acromial impingment
rotate, abduction
____ is the lateral aspect of the scapula that articulates with the humerus. What percentage of the humeral head articulates here?
glenoid fossa - 30%
_____ is the fibrocartilaginous tissue surrounding the glenoid fossa
functions? 3
Labrum
- serves as attachment for glenohumeral ligaments and tendons as well as the shoulder capsulel
- prevents anterior and posterior humeral head dislocation
- deepens the glenoid fossa and increases overall contact of the humeral head with the glenoid by 70% `
The glenohumeral capsule arises from ____ and covers the entire head of the humerus and attaches _____
labrum, neck of humerus
The glenohumeral capsule thickens anteriorly to form ____
glenohumeral ligaments
Name the 3 glenohumeral ligaments:
- Superior glenohumeral ligament
- Middle glenohumeral ligament
- Inferior glenohumeral ligament
Which GH ligament is the primary anterior stabilizer above 90 degrees?
inferior glenohumeral ligament
Which GH ligament limits anterior shoulder translation?
Middle glenohumeral ligament
Which GH ligament prevents shoulder translation in the inferior directioN?
Superior GH ligament
Which GH ligaments provide stability from 0-90 degrees of abduction?
Superior and middle glenohumeral ligaments
Name the dynamic stabilizers of the shoulder 6
- rotator cuff - Supraspinatus, Infraspinatus, Teres minor, Subscapularis
- Long head of biceps tendon
- Deltoid
- Teres major
- Latissiumus dorsi
6 Scapular stabilizers (traps, serratus anterior) play a supporting role in stabilizing the GH joint during ROM.
Name the static stabilizers of the shoulder joint 4
- Glenoid
- Labrum
- Shoulder capsule
- Glenohumeral ligaments (3)
The _____ ligament connects the distal end of the clavicle to the acromion, providing horizontal stability
acromioclavicular ligament
The ____ ligament connects the coracoid process to the clavicle and anchors the clavicle to the coracoid process, preventing vertical translation of the clavicle.
It is made up of what two parts?
Coracoclavicular ligament
Conoid (medial) & Trapezoid (lateral)
The ____ ligament attaches the coracoid process to the acromion
coraco-acromial ligament
two most common mechanisms of injury to AC ligaments:
- direct impact to the shoulder
2. falling on an outstretched arm
Describe the classification of AC joint separations
AC CC Clavicle
Type I partial sprain intact no displacement
Type II complete tear partial sprain no disp
Type III Complete Complete tear superior
Type IV Complete Complete Post and sup into trap, giving buttonhole appearance
Type V Complete Complete (more severe than III with CC space increased over 100%) Indicates disruption of deltoid and trapezius fibers Superior and posterior clavicle
Type VI Complete Complete inferior
In AC separation, if gross deformity is noted, it is at Type _____ or greater
III
what is the provocative test for AC joint impingement?
cross-chest (horizontal adduction or scarf) test: passive adduction of teh arm across the midline causing joint tenderness.
On Xray, AC joints separations:
1 Weighted how much?
2 Type III injuries may show ____% widening of the clavicularcoracoid area
3. Type V injuries may show ____% widening
- 10lb
- 25-100%
- > 100%
Treatment of AC joint injuries:
I - VI
I and II: RICE; NSAIDs; sling for comfort; return to play when asymptomatic with full ROM (I: 2 weeks, II: 6 weeks)
III: controversial; surgically treat heavy laborers or athletes.
IV-VI: surgery - ORIF or distal clavicular resection with recon of CC ligament
Chronic - CSI injection or surgery as above
What are the complications of AC joint injuries?
- associated fractures and dislocations
- distal clavicle osteolysis; degeneration of the distal clavicle with assoiciated osteopenia and cystic changes
- AC joint arthritis - may get relief from lidocaine injection
Name the 3 classifications of Glenohumeral joint instability
- instability - translation of the humeral head on glenoid fossa. may result in subluxation or dislocation
- Subluxation - incomplete separation of humeral head from the fossa with immediate reduction
- Dislocation - complete separation of the humeral head from the glenoid fossa without immediate reduction.
- With regard to glenohumeral instability, which is the most common direction?
- What age of the population?
- Mechanism?
- Complications?
- Anterior/inferior
- younger population with high recurrence rate
- Arm abduction and external rotation
- axillary nerve injury
Patient presents with an adducted and internally rotated arm. Etiology?
Posterior glenohumeral instability
likely result of seizure.
Mechanism of posterior glenohumeral instability?
landing on a forward flexed adducted arm, seizure
Discuss the two patterns of glenohumeral instability
Traumatic: T.U.B.S.
- T: Traumatic Shoulder Instability
- U: Unidirectional
- B: Bankart lesion
- S: Surgical management
Atraumatic. A.M.B.R.I.
- A: Atraumatic shoulder instability
- M: Multidirection instability
- B: Bilateral lesions
- R: Rehabilitation Management
- I: Inferior capsular shift, if surgery
Anterior dislocations of the glenohumeral joint can cause what two lesions?
- Bankart lesion - tear of the glenoid labrum off the anterior glenoid allowing the humeral head to slip anteriorly
- Hill-Sachs lesion - compression fracture of the posterolateral humeral head caused by abutment against the anterior rim of the glenoid fossa
In Bankart lesions,
- most commonly associated with _____ instability
- May be associated with ____
- anterior instability
2. avulsion fracture of the glenoid rim
_____ is a compression fracture of the posterolateral humeral head caused by abutment against the anterior rim of the glenoid fossa
hill-sachs lesion
With regard to hill-sachs lesions
- most common with ____ dislocations
- A lesions > _____% of the articular surface may cause instability
- A notch occurs on the posterior lateral aspect of the humeral head due to _____
- anterior
- 30%
- recurrent impingement
Posterior glenohumeral dislocations cause what lesions?
reverse bankhart and reverse hill sachs.
What pathology?
symptoms include early shoulder fatigue, pain, numbness, and parasthesia. Shoulder might slip in and out of place most commonly when the arm is placed in abduction and external rotation (“throwing position”)
Dead arm syndrome - seen in pitchers and volleyball players who require repetitive overhead arm motion.
What is the test for dead arm syndrome?
laxity exam: patient’s say they are “double jointed” which is lay term for capsular laxity.
- ask patient to touch the thumb against the volar (flexor) surface of the forearm.
- patients with lax tissues are more likely than others ot be able to voluntarily dislocate the shoulder.
Name the provocative tests for ANTERIOR glenohumeral instability (4)
- Apprehension test - feeling of anterior shoulder instability with 90 degrees shoulder abduction and external rotation, causing apprehension (fear of dislocation in the patient)
- Relocation test: supine apprehension test with a posterior directed force applied to the anterior aspect of the shoulder not allowing anterior dislocation. This force relieves the feeling of apprehension
- Anterior drawer test - passive anterior displacement of the humeral head on the glenoid
- Anterior load and shift test - essentially a modified form of the anterior drawer test; humeral head is loaded against the glenoid and then passively displaced anteriorly. positive if there is reproduction of the patient’s symptoms of instability, pain, and crepitation.
What are the three tests for posterior glenohumeral joint instability?
- Jerk test - place the arm in 90 degrees of flexion and maximum internal rotation with the elbow flexed to 90 degrees. Adduct the arm across the body in the horizontal plane while pushing the humerus in a posterior direction. The patient will jerk away when the arm nears midline to prevent posterior subluxation or dislocation of the humeral head.
- Posterior drawer test
- Posterior load and shift test.
What is the test for multidirectional glenohumeral instability?
sulcus sign: the examiner pulls down on the patient’s arm with one hand as he stabilizes the scapula with the other. If an indentation develops between the acromion and the humeral head, the test is positive. This suggests increased laxity in the GH joint.