Clinical Shoulder Flashcards
What is Scapulohumeral Rhythym
- Refers to the motion that occurs at the scapaulothoracic joint during elevation of the arm
- Normal Ratio is 2:1
- 2 deg of Glenohumeral motion for every 1 degree of Scapulothoracic
What Gliding Movement changes occur with surgical tightening of the Shoulder Joint Capsule?
- Obligate movement is said to occur whereby tightening of the posterior capsule or Rotator Interval increase Anterior Translation during forward elevation
- Excessive Anterior stability after repair can cause humeral head and joint contact posteriorly and can possibly lead to degenerative changes in the shoulder
What is the normal strength ratio of the shoulder in ER and IR?
External Rotators typically are about 66% as strong as the internal rotators
- Some (Davies, etc) have proposed during rehabilitation we should shoot for 75% to create a “Posterior Dominant” Shoulder
What ligament is typically contracted in shoulders with adhesive capsulitis?
- The Coracohumeral ligament
- This ligament prevents ER with arm at side and often needs to be released to regain full ER ROM
What is the rotator cuff interval?
- The capsular tissue in the interval between the Subscapularis and Supraspinaus Tendons
- It is composed of parts of the Subscapularis and Supraspinatus tendons as well as the Coracohumeral and Superior Glenohumeral ligaments
How can pathologic change to the rotator cuff interval affect the shoulder?
- If too tight, can limit ER and play a role in Adhesive Capsulitis
- If too lax, can play a role in Multidirectional Instability and Anteroinferior instability
What are the biomechanical effects of the Rotator Cuff?
- Depress the humeral head and counteract the Superior pull of the deltoid
- Maintain proper positioning of the humeral head within the glenoid
What is the Quadrangular Space, What Structures pass through it?
- Anatomic interval formed by shaft of the humerus laterally, long head of the biceps medially, teres minor superiorly and teres major inferiorly.
- It contains Axillary Nerve, Posterior Humeral Circumflex artery
What is the Triangular Space, What structures pass through it?
- Anatomic interval bordered by long head of biceps laterally, teres minor superiorly, and teres major inferiorly
- It contains the circumflex scapular artery and a branch of the scapular artery
Which ligaments provide static prevention of anterior translation of the humeral head, and in which positions do they perform this action?
- Anterior Band of the Inferior Glenohumeral ligament in the ER9090 position
- Middle Glenohumeral ligament in midrange shoulder elevation
- Superior Glenohumeral ligament prevents ER and Inferior Translation with arm at side
What is a Bankart Lesion?
- Detachment of the anchor point of the Anterior Band of Inferior Glenohumeral and middle Glenohumeral ligaments
- Often occurs as a result of traumatic Anterior Dislocation of the shoulder
What is a Hill Sachs Lesion?
- Impression fracture to the posterolateral margin of the humeral head
- Caused by impaction on the rim of the glenoid during Anterior Dislocation
- If lesion involves >30% of the articular surface of the humerus, can lead to recurrent instability
Where does the Suprascapular nerve sometimes become compressed and what deficits would be present?
- Suprascapular Notch and Spinoglenoid notch
- If at Suprascapular, Supraspinatus and Infraspinatus would be affected
- If at Spinoglenoid, Infraspinatus would be affected
Which nerve is at greatest risk during Anterior Shoulder Surgery?
- Axillary nerve
Which Nerve Superficial to the Posterior Cervical Triangle and is susceptible to injury?
- Cranial Nerve XI (Spinal Accessory Nerve)
Injury to which nerve causes Classic Medial Scapular Winging?
- Long Thoracic Nerve
What is Os Acromiale?
- An unfused acromial epiphysis. Failure of the distal end of the acromion to ossify
What are the Three Types of Acromion Shape?
- Type 1: Flat
- Type 2: curved downward
- Type 3: Hooked
- Much higher incidence of RTC tears in type 3 and 2 than type 1
What are the Four Stages of Neers Rotator Cuff Pathology Classification?
- Stage I: Edema and Hemmorhage
- Stage 2: Fibrosis and Tendinitis
- Stage 3: Bone Spur and Tendon Rupture
- Stage 4: Cuf Tear Arthropathy
What is the Coracoacromial Arch?
- The Coracoacromial Ligament. It acts as the roof of the Glenohumeral joint and can compress tissue when humeral elevation and internal rotation occurs.
What are the two types of Subacromial Decompression?
- Open and Arthroscopic
- Some doctors prefer one or the other, but if a massive RTC tear is found during the procedure it is more easily repaired when open.
What is a Mumford Procedure?
- Distal Clavicular Excision/ Removal
- Removal of distal 2cm
Describe Primary vs. Secondary Shoulder impingement
- Primary is mechanical and caused by joint space overcrowding
- Secondary is typically due to instability
What is Posterior (Internal) Impingement?
- Pinching of the Infraspinatus and Supraspinatus between the posterior superior aspect of the glenoid
- Typically seen in throwers, symptomatic when in the cocking position or phase of throwing