First Palmar (Volar) Interosseous Muscle Exam

  • The palmar interosseous muscles are difficult to see or palpate.
  • The palmar interosseous muscles adduct the fingers, flex the MP joints, and extend the PIP and DIP joints.  Therefore, their function can be assessed by evaluating active and passive range of motion in these planes.
  • The excursion of the palmar interosseous muscles can also be assessed by the Bunnell intrinsic tightness test.
Diagrams & Photos
  • The palmar interosseous muscles adduct the fingers towards the central long finger ray (red line).
    The palmar interosseous muscles adduct the fingers towards the central long finger ray (red line).
  • The interossei contribute to the intrinsic plus position by flexing the MP joints and extending the PIP and DIP joints.
    The interossei contribute to the intrinsic plus position by flexing the MP joints and extending the PIP and DIP joints.
  • Fingers adducting towards the central long finger ray (red line) against resistance during muscle testing of the palmar interosseous muscles.
    Fingers adducting towards the central long finger ray (red line) against resistance during muscle testing of the palmar interosseous muscles.
Key Points
  • The first volar interosseous muscle compartment pressure can be measurer with a manometer.
Grading of Muscle Strength
Exam References
Anatomic Abbreviations
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