2.1 Shoulder & Upper Extremity Diagnostics

2.1 Shoulder & Upper Extremity Diagnostics

Physical Medicine and Rehabilitation (PM&R) physicians must master the diagnostic evaluation of shoulder and upper extremity disorders. Accurate diagnosis relies on integrating anatomical knowledge, targeted history, and structured physical examination maneuvers.

Rotator Cuff Pathology

The rotator cuff consists of four muscles that stabilize the glenohumeral joint and execute multiplanar movements: the supraspinatus (abduction, dynamic humeral head depression), infraspinatus (external rotation), teres minor (external rotation with shoulder abducted), and subscapularis (internal rotation). Spectrum of pathology ranges from subacromial tendinopathy to full-thickness tears and rotator cuff tear arthropathy.

Clinical Examination of Rotator Cuff Muscles

• Supraspinatus: Tested via the Jobe / Empty Can test (shoulder abducted 90° in scapular plane, internally rotated with thumb down; resisted downward pressure). The Full Can test (thumb up) provides equal accuracy with less pain. Massive tears present with a positive Drop Arm test (inability to lower arm smoothly from full passive abduction).
• Infraspinatus & Teres Minor: Evaluated with resisted external rotation at the side. An External Rotation Lag sign indicates severe infraspinatus and supraspinatus tears. The Hornblower sign (arm held in 90° abduction, flexed 90° at elbow; positive if arm drops into internal rotation during resisted external rotation) isolates teres minor pathology.
• Subscapularis: Tested via the Gerber Lift-Off test (lifting dorsum of hand off lumbar spine). If internal rotation range of motion is restricted, the Belly Press test or Bear Hug test are sensitive alternatives.

Subacromial Impingement Syndrome

Subacromial impingement involves dynamic or structural compression of the supraspinatus tendon, subacromial bursa, and long head of biceps tendon beneath the coracoacromial arch. Structural factors include acromial morphology, categorized by Bigliani classification:

• Type I: Flat (lowest association with tears).
• Type II: Curved (parallel to humeral head).
• Type III: Hooked (highest correlation with rotator cuff tears).

Provocative Impingement Signs

• Neer Impingement test: Examiner stabilizes scapula while passively flexing the patient's arm overhead in maximal internal rotation (forearm pronated). Pain indicates positive impingement.
• Hawkins-Kennedy test: Shoulder flexed 90° with elbow flexed 90°. Passive forced internal rotation compresses supraspinatus against coracoacromial ligament.
• Neer Diagnostic Injection Test: Subacromial injection of 10 mL 1% lidocaine. Relief of pain confirms subacromial impingement vs cervical or intra-articular pathology.

Adhesive Capsulitis (Frozen Shoulder)

Adhesive capsulitis is characterized by chronic inflammation, hypervascular synovitis, and progressive capsular fibrosis leading to contracture of the glenohumeral capsule, particularly the coracohumeral ligament and rotator interval.

Risk Factors and Pathophysiology

Strongly associated with Diabetes Mellitus (incidence up to 20%), thyroid disorders, Dupuytren disease, Parkinson disease, post-cardiac surgery, and prolonged immobilization. Female sex and age 40–60 years are major demographic risk factors.

Clinical Stages

1. Stage 1 (Pre-freezing / Painful Phase) (0–3 months): Insidious onset of severe achy night pain. Minimal motion loss.
2. Stage 2 (Freezing Phase) (3–9 months): Severe pain with progressive loss of active AND passive motion in a classic capsular pattern: External Rotation > Abduction > Internal Rotation.
3. Stage 3 (Frozen Phase) (9–15 months): Pain decreases, but severe global motion restriction persists with a fibrotic capsular end-feel.
4. Stage 4 (Thawing Phase) (15–24+ months): Pain is minimal. Slow, spontaneous regain of shoulder range of motion.

Acromioclavicular (AC) Joint Pathology

Acromioclavicular joint disorders arise from post-traumatic separation or degenerative acromioclavicular osteoarthritis.

• Cross-body Adduction test: Shoulder flexed to 90° and passively adducted across chest. Localized pain over the AC joint confirms AC pathology.
• O'Brien Active Compression test: Shoulder flexed to 90°, adducted 10°, internally rotated (thumb down); downward force is applied. Test repeated in supination (thumb up). Superior AC joint pain in thumb-down position indicates AC arthritis; deep intra-articular pain indicates a Superior Labrum Anterior to Posterior (SLAP) lesion.
• AC Shear test: Squeezing anterior acromion and posterior clavicle together compresses the AC joint, reproducing pain.

Glenohumeral Instability

Glenohumeral instability spans traumatic anterior subluxation to atraumatic multidirectional instability.

Diagnostic Classification

• TUBS: Traumatic, Unidirectional, Bankart lesion, Surgery indicated (anterior-inferior disruption).
• AMBRI: Atraumatic, Multidirectional, Bilateral, Rehabilitation first-line, Inferior capsular shift if non-operative care fails. Associated with systemic hypermobility (Beighton score ≥ 5/9).

Physical Exam Maneuvers

• Apprehension Test: Patient supine; shoulder abducted 90° and passively externally rotated. Positive sign is subjective sense of impending dislocation.
• Relocation Test: Posterior-directed force on anterior proximal humerus relieves apprehension and allows further external rotation.
• Surprise / Release Test: Sudden removal of relocation force causes immediate return of apprehension.
• Sulcus Sign: Downward traction at elbow with arm at side; visible depression (>1–2 cm) below acromion indicates inferior instability.

Bicipital Tendinopathy and Subluxation

The long head of the biceps tendon (LHBT) travels inside the bicipital groove held by the transverse humeral ligament and rotator interval roof.

• Speed Test: Resisted shoulder flexion with elbow extended and forearm supinated. Bicipital groove pain indicates tendinopathy or SLAP lesion.
• Yergason Test: Resisted forearm supination and external rotation with elbow flexed 90°. Bicipital groove pain indicates tendinopathy; a palpable pop indicates transverse ligament disruption with biceps tendon subluxation.