Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Shoulder Anatomy and Examination

Basics
Description
  • Bones:
    • Glenohumeral joint:
      • The humeral head articulates with the glenoid fossa of the scapula.
      • Stabilized by the glenohumeral ligaments capsule and rotator cuff muscles
      • The labrum of the glenoid deepens the joint and enhances stability.
    • AC joint:
      • The acromion process of the scapula articulates with the distal clavicle.
      • Suspends the arm and scapula
    • Sternoclavicular joint:
      • The sternum articulates with the proximal end of clavicle.
      • Suspends the arm and scapula
    • Scapulothoracic joint:
      • Consists of the body of the scapula and the muscles covering the posterior chest wall
      • Contributes to shoulder flexion and rotation
  • Muscles:
    • The trapezius, levator, rhomboids, and serratus anterior stabilize the scapula to aid motion at the glenohumeral joint.
    • Deltoid: Flexor, abductor, and extensor
    • Rotator cuff:
      • Supraspinatus: Abductor and external rotator
      • Infraspinatus: External rotator
      • Teres minor: External rotator
      • Subscapularis: Internal rotator and adductor
    • Pectoralis major: Adductor
    • Coracobrachialis and biceps: Flexors
  • Nerves:
    • Brachial plexus:
      • Passes through the axilla
      • Branches originate in the neck from C5-T1.
    • Axillary nerve:
      • Innervates the deltoid
      • May be injured in anterior shoulder dislocations
    • Musculocutaneous nerve: Innervates the biceps and coracobrachialis
Diagnosis
Signs and Symptoms
History
Thorough history of the mechanism of injury and the nature of pain
Physical Exam
  • Initial assessment:
    • Assess the cervical spine and elbow.
    • Perform a complete neurovascular examination of the extremities.
    • Assess the contralateral shoulder for comparison.
  • Inspection:
    • Expose both upper extremities from the shoulder girdle to the hand, inspecting for asymmetry, atrophy, and scapular winging.
  • Palpation:
    • Palpate the sternoclavicular joint, clavicle, AC joint, coracoid, acromion, glenohumeral joint, bicipital groove, and the greater and lesser tuberosities of the humerus.
    • Localize the pain.
  • ROM:
    • Compare active and passive ROM.
      • Forward flexion: 180°
      • Extension: 50-60°
    • Motion:
      • Assess in adduction and abduction.
      • Distinguish glenohumeral motion from combined glenohumeral and scapulothoracic motion (combined values).
      • External rotation: 80-90°
      • Internal rotation: 60-80°
      • Abduction: 160-180°
Tests
  • Biceps tendinitis:
    • Pain to palpation in the bicipital groove, found anteriorly on the shoulder with the arm at 10° of internal rotation
    • Yergason test:
      • Test resisted forearm supination with the elbow flexed at 90°.
      • Test is positive when pain is reproduced in the bicipital groove.
    • Speed test:
      • With the elbow extended, the forearm supinated, and the shoulder flexed at 60°, ask the patient to resist additional forward flexion of shoulder.
      • The test is positive when pain is reproduced in the bicipital groove.
  • Subacromial bursitis:
    • Presentation is very similar to that of rotator cuff tendinitis.
    • Patient may present with subacromial crepitus.
  • Rotator cuff tear:
    • Diffuse, dull, aching pain localized over the deltoid and upper arm
    • Pain with overhead activities
    • Tenderness to palpation over the greater tuberosity of the humerus
    • Test individual rotator cuff muscles for weakness and or pain.
      • Supraspinatus: Test the patient’s strength in active arm elevation in the plane of the scapula with the patient’s thumb pointing down.
      • Infraspinatus and teres minor: Test the patient’s strength in active external rotation with the patient’s arm at the side and the elbow flexed at 90°.
      • Subscapularis (belly press test): Place both of the patient’s hands on his/her belly; have the patient press the belly inward while thrusting elbows forward; the test is positive if the elbow cannot be actively moved forward.
    • Neer sign:
      • Elevate the arm while stabilizing the scapula.
      • Positive sign: Pain at maximal elevation
    • Hawkins test:
      • With the patient’s elbow flexed at 90°, forward flex the shoulder to 90° and internally rotate the humerus.
      • The test is positive if pain is reproduced on contact of the greater tuberosity with the acromion.
    • Painful arc:
      • Active abduction in the coronal plane
      • The test is positive with pain at 60-100° of abduction.
      • Pain is common in tendinitis and small rotator cuff tears
    • Drop-arm test:
      • Inability to hold arm up when passively positioned into an elevated position
      • Suggests a large tear
    • Weakness, inability to elevate, and passive ROM that exceeds active ROM also suggest rotator cuff tear.
    • Popeye sign:
      • The biceps resembles a Popeye muscle when resisted elbow flexion is tested.
      • Indicates a proximal rupture of the biceps tendon
      • Note: Also occurs with distal biceps tendon rupture
  • Shoulder instability:
    • History of previous dislocations
    • Patient complains of instability with or without pain.
    • Anterior instability: Apprehension with 90/90 positioning (90° of abduction and 90° of external rotation)
    • Posterior instability: Apprehension with humeral forward flexion in internal rotation
    • Load and shift test:
      • With the humerus in a neutral position on the glenoid, axially load the humerus and shift the head anteriorly and posteriorly.
      • Excessive translation resulting in palpable subluxation and/or dislocation is a positive finding.
    • Sulcus sign:
      • With the affected elbow flexed, apply inferior traction to the arm and look for skin dimpling near the lateral acromion.
      • Dimpling indicates inferior instability.
  • AC joint arthritis/AC separation:
    • Palpable point tenderness at the AC joint
    • Palpable step-off at the AC joint in the presence of a separation
    • Joint effusion may be present.
    • Cross-body adduction test:
      • With the shoulder at 90° of flexion, passively adduct the arm.
      • The test is positive when pain is reproduced at the AC joint.
  • Labrum abnormality:
    • Patient describes pain as deep in the shoulder and occurring with overhead activities.
    • Patient may have anterior or posterior joint line tenderness.
    • Active compression test:
      • Position the affected arm as for the cross-body adduction test.
      • With the elbow extended, and the humerus internally rotated (thumb down), test resisted humeral elevation.
      • Positive test: Pain is elicited when in internal rotation but relieved when the test is repeated in external rotation (thumb up).
      • Pain localized deep in the shoulder is indicative of biceps or labral abnormality.
      • Pain at the top of the shoulder indicates AC abnormality.
      • Pain elsewhere is equivocal.
  • Glenohumeral joint arthritis:
    • Start-up pain on initiation of activity
    • Palpable joint-line tenderness
    • Decreased active and passive ROM
    • Active and passive ROM are equal.
    • Pain at the extremes of motion in all planes
    • Glenohumeral crepitus with motion
  • Adhesive capsulitis:
    • Palpable joint line tenderness
    • Severely decreased ROM
    • Active and passive ROM are equal.
    • Pain with motion in all planes
Miscellaneous
FAQ
Q: What are the most common causes of atraumatic shoulder pain?
A: Rotator cuff disease, AC joint arthritis, cervical radiculopathy.
Q: What is the difference between a shoulder separation and a shoulder dislocation?
A: A shoulder separation is a dislocation of the AC joint. A shoulder dislocation is a dislocation of the glenohumeral joint.

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