What does the Apley's scratch test indicate about shoulder joint function?

Apley's Scratch Test for Shoulder Joint Function Assessment

The Apley's scratch test evaluates shoulder range of motion, particularly internal rotation, and can identify functional limitations that may indicate underlying shoulder pathology.

Purpose and Execution

The Apley's scratch test is a clinical examination technique that assesses shoulder mobility by evaluating a patient's ability to reach specific anatomical landmarks behind their back. This test primarily evaluates:

• Internal rotation of the shoulder
• Adduction of the shoulder
• Scapular mobility

Interpretation of Results

Normal Function

• Ability to reach the lumbosacral junction or higher (between the scapulae)
• Symmetrical performance between both shoulders

Abnormal Function

• Insufficient internal rotation: Inability to reach the lumbosacral junction 1
• Limited range of motion may indicate:
  • Rotator cuff pathology
  • Adhesive capsulitis (frozen shoulder)
  • Glenohumeral arthritis
  • Post-surgical limitations
  • Hemiplegic shoulder pain 2

Clinical Significance

1. Post-surgical evaluation: Particularly valuable after shoulder arthroplasty to assess functional outcomes

   • In bilateral reverse shoulder arthroplasty patients, approximately 21% had insufficient internal rotation (unable to reach lumbosacral junction) after the first procedure, and 33% after the second procedure 1
   • Only 5% of patients had insufficient internal rotation on both sides at 2-year follow-up 1

2. Functional assessment: Provides insight into a patient's ability to perform activities of daily living that require internal rotation (e.g., toileting, dressing)

3. Rehabilitation monitoring: Can track progress during physical therapy for shoulder conditions

Limitations

• The test is primarily qualitative rather than quantitative
• Results may be affected by:
  • Pain inhibition
  • Patient effort
  • Compensatory movements from the scapula or spine
  • Concomitant shoulder pathologies

Comparison to Other Tests

Unlike specialized tests such as the scratch collapse test (used for nerve compression syndromes) 3, 4, the Apley's scratch test specifically evaluates shoulder range of motion rather than neurological function.

For comprehensive shoulder assessment, the Apley's test should be considered alongside other examinations:

• External rotation assessment
• Forward flexion measurement
• Abduction testing
• Specific tests for rotator cuff pathology
• Imaging when indicated 2

Clinical Application

When a patient demonstrates limited internal rotation on the Apley's scratch test, further evaluation may be warranted, including:

• Detailed history of shoulder trauma or symptoms
• Additional physical examination maneuvers
• Appropriate imaging studies based on clinical suspicion 2

The test provides valuable functional information but should be interpreted within the context of the patient's overall clinical presentation and other examination findings.