Flashcards in Shoulder Deck (40):
The shoulder region possesses less mechanical _____ and less bony _____ than any other large joint in body
What 2 radiographic views are recommended as an initial study for all trauma cases to the shoulder?
- Axillary or scapular Y
When is an MRI of the shoulder recommended?
For acute and subacute shoulder pain if the initial radiograph is normal, or RC pathology, instability, or labral tears are suspected
When is a CT of the shoulder recommended?
When the MRI is unavailable or contraindicated
The 4 tendons of the RC muscles fuse to form what?
The ﬁbrous capsule of the GH joint
RC tears may result for what 3 MOIs?
- GH dislocation
- Fall on outstretched hand
- Forceful abduction of arm
What is a non-traumatic MOI for a RC tear?
Progressive tendon irritation caused by repetitive overhead movements or impingement
Where does the most common RC tear occur?
In the hypovascular critical zone of the supraspinatus tendon 1 cm above its insertion on greater tuberosity
How are complete RC tears diagnosed via radiographs (arthrography)?
A complete RC tear will allow the contrast medium to travel up through the tear and fill the subacromial-subdeltoid bursa, this causes the bursa to be radiopaque
How are incomplete RC tears diagnosed via radiographs (arthrography)?
There is a collection of contrast medium at the tear site
When is an arthrography recommened in the diagnosis of a RC tear?
Only when the patient cannot have MRI and ultrasound expertise is not available
What are the 3 secondary changes in chronic RC tears that are evident on radiographs?
1) Irregularity of the greater tuberosity
2) Narrowing of the distance between the acromion and humeral head
3) Erosion of the inferior aspect of the acromion
How may the greater tuberosity appear in chronic RC tears? Why?
Flattened, atrophied, or sclerotic because of the rupture of the supraspinatus tendon and lack of traction stress at insertion site.
What are the 2 reasons why there is a narrowing of the distance between the acromion and humeral head in chronic RC tears?
- There is atrophy of the cuff muscles
- The weak RC muscles do not oppose the pull of the deltoid muscle
In chronic RC tears the humeral head migrates ____.
The upward migration of the humeral head may cause changes to what bony structure?
What are most complications following a RC tear due to?
Degenerative changes at the GH and AC joints
Failure to regain full ROM and strength following RC repair surgery can lead to what?
- Impaired scapulohumeral rhythm
- Chronic tendon irritation and inﬂammation
- Poor function
A "SICK" scapula may develop following RC tear, what does this stand for?
S = Scapular malposition
I = Inferior medial border prominence
C = Coracoid pain and malposition
K = DysKinesis of the scapula
Describe the positioning of a "SICK" shoulder
It sits inferior, lateral, and is upwardly rotated
A "SICK" scapula represents with pain in what 4 distributions?
- Postero-superior scapular pain
- Anterior shoulder pain
- Proximal lateral arm pain
- C-spine pain
What are the 3 types of scapular dyskinesis?
- Type I: Inferior medial scapular prominence
- Type II: Medial scapular border prominence
- Type III: Superomedial border prominence
Type I and type II scapular dyskinesias are associated with what?
Type III scapular dyskinesia is associated with what?
impingement and rotator cuff lesions
What are the 2 basic functions of the labrum?
- deepen the glenoid fossa so the humeral head stays in place
- serve as attachment site for capsular ligaments and the biceps tendon
What are the symptoms of a labral tear?
- pain that is worse with overhead movements
- clicking or catching
- sense of instability
What are the 3 acute MOIs for a labral tear?
- forceful lifting manuever
- fall on an outstretched hand
What can also injure the labrum?
Repetitive movements of the arm, especially in overhead athletes
What aspects of the labrum are susceptible to injury in overhead athletes?
Biceps tendon stress at the superior labral attachement as well as repetitive impingement of the posterior humeral head against the rotator cuff and labrum
The action of throwing overhand includes high velocity abduction and ER rotation during the cocking phase, which ligaments are twisted and elongated?
The middle GH ligament and anterior band of the inferior GH ligament
The active motion produce during the cocking phase of throwing tends to translate the humeral head _____, toward what structures?
anteriorly, toward the anterior glenoid labrum and the subscapularis muscle
Other than overhead throwing, what may be cause abnormal shear forces at labrum?
Muscle imbalances that decentralize the position of the humeral head within the glenoid fossa which can trigger a cascade of abnormal shoulder biomechanics
What is the most appropriate procedure to assess suspected instability and labral tears?
An MR anthrography
What is an advantage of MR anthrology in detecting labral pathologies?
The contrast medium distends the joint permitting better visualization
What is the second procedure of choice when assessing suspected instability and labral tears?
How are labral tears treated?
Conservatively, due to the rich blood supply to the labrum
What are 3 surgical interventions for labral tears?
- Avulsions are reattached to glenoid rim with sutures and anchors
- Torn edges of minor tears debrided, whereas.large tears require suture repair
- Biceps tenodesis surgery
When are biceps tenodesis performed
In patients with labral tears over the age of 40
Describe the procedure behind a biceps tenodesis
The biceps is cut from where it attaches to labrum and reinserted into another area on the labrum