Infraspinatus Test

The Infraspinatus Test is used to assess the function of the infraspinatus muscle, a key component of the rotator cuff responsible for shoulder external rotation and glenohumeral stabilization. Weakness or injury in this muscle may lead to shoulder pathologies such as subacromial impingement or rotator cuff tears. The infraspinatus works synergistically with the supraspinatus, subscapularis, and teres minor to keep the humeral head centered in the glenoid, preventing cranial migration during arm movements.

Purpose

The test aims to:

• Detect weakness or injury in the infraspinatus muscle

• Evaluate pain response during resisted external rotation

• Differentiate infraspinatus involvement from other rotator cuff injuries (especially supraspinatus and subscapularis)

Relevant Anatomy

The infraspinatus originates in the infraspinous fossa of the scapula and inserts on the greater tubercle of the humerus. It is innervated by the suprascapular nerve. Functionally, it provides external rotation of the shoulder and contributes significantly to stabilization of the humeral head. Failure or rupture leads to reduced rotational strength, pain, and loss of function.

Test Procedure

Patient position:

• Patient sits or stands with arms relaxed but not pressed against the torso

• Elbows flexed to 90°

Movement:

• Examiner places hands on the dorsal side of the patient’s hands

• Patient is instructed to externally rotate against examiner resistance

Observation:

• Positive test: Pain or weakness during external rotation

  • Pain → possible subacromial impingement or mild cuff pathology

  • Weakness without pain → strongly suggests infraspinatus tear

Physiotutors.com

Interpretation

• Positive test: Localized pain or weakness in resisted external rotation

• Negative test: Full strength and no pain during external rotation

Evidence

• Sensitivity: ~0.90 (high – good at detecting pathology)

• Specificity: ~0.74 (moderate – false positives possible)

• Diagnostic accuracy improves when included in test clusters.

Test Clusters

Subacromial Impingement

• Combination: Hawkins-Kennedy + Painful Arc + Infraspinatus Test

• All three positive: LR+ 10.56

• All three negative: LR– 0.17

• Two of three positive: LR+ 5.03

Full-Thickness Rotator Cuff Tear

• Combination: Drop-Arm Test + Painful Arc + Infraspinatus Test

• All three positive: LR+ 15.6

• All three negative: LR– 0.16

• All three positive + age >60: LR+ 28.0

• Two of three positive: LR+ 3.60

Clinical Relevance

• The test is quick, simple, and highly sensitive for infraspinatus dysfunction

• A negative test significantly reduces the likelihood of major injury

• A positive test should be interpreted alongside other shoulder tests and imaging

• Valuable in both acute and chronic shoulder pain assessment

Limitations

• Moderate specificity means false positives may occur

• Pain inhibition, compensatory strategies, or misunderstanding instructions can alter results

• Cannot differentiate partial vs. full-thickness tears on its own

Summary

The Infraspinatus Test is a sensitive and practical clinical tool to assess infraspinatus muscle function. Conducted with the elbow flexed at 90° and resisted external rotation, a positive finding indicates pain or weakness consistent with infraspinatus injury. While useful alone, the test is most powerful when included in diagnostic clusters for subacromial impingement or rotator cuff tears.

Sources:

1. Hughes PC, Green RA, Taylor NF. Isolation of infraspinatus in clinical test positions. Journal of science and medicine in sport. 2014 May 1;17(3):256-60.

2. Micheroli R, Kyburz D, Ciurea A, Dubs B, Toniolo M, Bisig SP, Tamborrini G. Correlation of findings in clinical and high resolution ultrasonography examinations of the painful shoulder. Journal of ultrasonography. 2015 Mar;15(60):29.

3. Tim Fraticelli - PTProgress. Infraspinatus Test | Rotator Cuff Tendonitis or Tear . Available from: http://www. https://www.youtube.com/watch?v=gPDN7XIA-KI

4. Park, H.B., Yokota, A., Gill, H.S., EI RG, McFarland, E.G. (2005). Diagnostic accuracy of clinical tests for the different degrees of subacromial impingement syndrome. J Bone Joint Surg Am, 87(7), 1446-1455.

5. Park, H.B., Yokota, A., Gill, H.S., EI RG, McFarland, E.G. (2005). Diagnostic accuracy of clinical tests for the different degrees of subacromial impingement syndrome. J Bone Joint Surg Am, 87(7), 1446-1455.