Fourth Dorsal Interosseous Muscle Exam

  • The dorsal interosseous muscles are difficult to see or palpate.
  • The dorsal interosseous muscles abduct 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 dorsal interosseous muscles can also be assessed by the Bunnell intrinsic tightness test. 
Diagrams & Photos
  • The dorsal interosseous muscles abduct the fingers.
    The dorsal interosseous muscles abduct the fingers.
  • Fingers abducting away from the central long finger ray (red line) against resistance during muscle testing of the dorsal interosseous muscles.
    Fingers abducting away from the central long finger ray (red line) against resistance during muscle testing of the dorsal interosseous muscles.
  • 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.
Key Points
  • The fourth dorsal interosseous muscle compartment pressure can be measurer with a manometer.
  • The fourth dorsal metacarpal artery is located in the intrinsic compartment of the fourth dorsal interosseous muscle.
Grading of Muscle Strength
Exam References
Anatomic Abbreviations
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