Pinch Grip Test

The Pinch Grip Test is a precision grip assessment used to evaluate finger strength and fine motor function. It is frequently performed in occupational therapy, physiotherapy, and occupational health evaluations, including functional capacity evaluations (FCE) and neurological assessments.

Nøkkelgreps-test

Theoretical Basis

The test is based on a spinal inhibition reflex, where painful cutaneous stimulation causes a brief suppression of voluntary muscle activity.

• External rotation of the arm is a naturally weak movement, making it suitable for assessing this inhibitory reflex

• When the median or ulnar nerve is stimulated by scratching over the compression site, this may cause a brief weakness in external rotation, resulting in a “collapse” of the arm

• Positive test: A temporary loss of resistance against applied force, indicating nerve compression at the affected site¹

Execution of the Test

The test is performed using a pinch dynamometer or pinch gauge. The patient is seated with:

• Elbow flexed to 90°

• Upper arm adducted against the body

• Forearm in neutral position

Test variations:

• Lateral pinch (key pinch):

  • Place the pinch gauge between the thumb and the radial side of the index finger

  • Instruct the patient to pinch as hard as possible

• Three-point pinch (three-jaw chuck):

  • Place the pinch gauge between the pulp of the thumb, index, and middle finger

  • Instruct the patient to pinch maximally

• Two-point pinch (tip-to-tip grip):

  • Place the pinch gauge between the tip of the thumb and the tip of the index finger

  • The patient pinches as hard as possible

Each test is repeated three times, and the average is calculated for a reliable measurement. Equipment should be calibrated annually¹.

Utførelse av pinch grip test for nervekompresjon

Evidence and Diagnostic Properties

• A study of 119 patients with carpal tunnel syndrome and 70 with cubital tunnel syndrome compared SCT with Tinel’s sign and flexion/compression tests. Results showed higher sensitivity for SCT²

• A prospective blinded study (2020), however, demonstrated lower sensitivity and poor interrater reliability compared with electrophysiological tests³

• SCT shows high specificity but variable sensitivity, suggesting that it should not be used alone but rather as part of a broader diagnostic assessment¹

The test may be a useful supplement to other clinical examinations, but it should not be relied upon in isolation to diagnose nerve compression.

Summary

The Scratch Collapse Test (SCT) is a simple clinical maneuver based on a reflex inhibition mechanism, designed to detect nerve compression such as carpal tunnel or cubital tunnel syndrome. Although specific, its inconsistent sensitivity and reliability mean it should only be used in combination with other diagnostic methods.

Sources

1. Prohealth Pinch Gauge Norms And Testing Protocols https://www.prohealthcareproducts.com/pinch-gauge-norms-and-testing-protocols/

2. kuhealthprofessionals Pinch test Available from: https://www.youtube.com/watch?v=_UPRomXnw-k

3. David J. Magee. Orthopedic Physical Assessment. 6th edition. Elsevier. 2014.

4. Precision- Pinch Grip. Available from: https://functionalanatomyofthehand.wordpress.com/2016/04/14/precision-pinch-grip-2/

5. Anterior interosseous nerve syndrome. Available from: https://radiopaedia.org/articles/anterior-interosseous-nerve-syndrome-1

6. Cooper C. Fundamentals of hand therapy. Mosby; 2014.Available from:https://www.sciencedirect.com/topics/nursing-and-health-professions/pinch-strength