2 degrees of G-H elevation for 1 degree of scapular elevation
Anterior translation of G-H occurs with:
forward elevation above 55 degrees
Posterior translation of the G-H occurs with:
ext > 35 degrees
Strength ratios of the shoulder: IR vs ER
Strength ratios of the shoulder: Add to Abd
Strength ratios of the shoulder: Ext to flex
Which G-H ligament plays an important role to limited ER with the arm at the side and is frequently contracted in shoulders with adhesive capsulitis?
What is the rotator interval?
Space between the subscapularis tendon and the supraspinatus tendon including the coracohumeral ligament and the gleno superior glenohumeral ligament that provides significant amount of stability
What are the four parts of the proximal humerus?
1.) Shaft 2.) Greater tuberosity 3.) lesser tuberosity 4.) head
What are the basic biomechanical functions of the rotator cuff?
Provide stability through force couples and aid in motion about the G-H joint. Depresses the humeral head counteracting the superior pull of the deltoid
Describe the role of the long head of the biceps?
Opinions vary: anterior stability by depressing the humeral head, while also providng strength for elbow flexion, supination, abduction
What is the role of the bicipital groove in anterosuperior shoulder pain?
Differential diagnosis of RTC pathology, AC joint pain, instability, bicep tendons disease. Radiographic degenerative changes helps pin point anterior superior shoulder joint pain to the biceps tendon. These changes include stenosis and osteophyte formation in the groove.
What is the quadrangular space? Which structures pass through it?
Shaft of the humerus, long head of the triceps, teres minor, teres major; the axillary nerve and scapular artery passes through it
What is the triangular space? Which structures pass through it?
Long head of the triceps, teres minor, teres major; the circumflex scapular artery
How is the GHJ stability maintained?
Joint capsule and ligaments which tighten at extremes; RTC and deltoid are dynamic stabilizers function most at mid range
Which structure is the most important static restraint to anterior G-H translation in the 90 degree abducted ER position?
Anterior band of the inferior glenohumeral ligament
What movement does the middle glenohumeral ligament prevent?
anterior translation in the mid range of elevation
What does the superior glenohumeral ligament appear to prevent?
Excessive ER and inferior translation
What is a bankart lesion?
Lesion of the glenoid labrum corresponding to the detachment of the anchoring point of the anterior band of the inferior G-H ligament and middle G-H ligament from the glenoid rim.
What is a HAGL lesion?
represents an uncommon avulsion of the humeral attachment of the glenohumeral ligament
What is a Hill-Sachs lesion and how does it relate to recurrent anterior shoulder instability?
An impression fracture of the posteriorlateral margin of the humeral head caused by impaction on the rim of the glenoid during an anterior shoulder dislocation. Large fractures >30% of the surface contribute to instability
What is the biomechanical function of the clavicle?
A strut between the shoulder girdle and the axial skeleton; improve biomechanical efficiency
Define os acromiale:
unfused acromial epiphysis
What are the three types of acromion:
Type I: flat; Type II downward curve; type III hooked downward
Decribe Neer's classification of rotator cuff pathology:
Stage I: edema and hemorrhage; stage II fibrosis and tendinitis; Stage III bone spur and tendon rupture; stage IV cuff tear arthropathy
What is a partial thickness RTC tear?
With age degeneration or tensile failure of the RTC begins deep within the tissue; can progress to full thickness
Do partial thickness tears heal or progress?
They attempt to heal but most progress to full thickness tears
What is rotator cuff arthorpathy?
Massive tearing , cuff tendon slide off the humeral head causing it to elevate vs depress the humeral head. This causes degeneration.
When are acromioplasty and subacromial decompression required?
Recurrent pain with activity that does not always abate with rest and has failed conservative treatment.
What is primary cuff impairment?
mechanical impingement of the rotator cuff beneath the coracoacromial arch and typically results from subacromial overcrowding