Orbital floor fractures are more likely associated with which forced duction test result?

Study for the NBEO Ocular Disease Part 1 Test. Use flashcards and multiple choice questions, each with hints and explanations, to prepare for your exam! Get ready for your success!

Multiple Choice

Orbital floor fractures are more likely associated with which forced duction test result?

Explanation:
The key idea is distinguishing mechanical restriction from nerve or muscle weakness using the forced duction test. A positive forced duction test means there is a physical barrier preventing the eye from moving when the examiner tries to move it passively—you feel resistance. In orbital floor (blow-out) fractures, the inferior rectus muscle or orbital tissue can become trapped in the fracture site, creating a mechanical tether. This entrapment restricts movement, especially upward gaze, so the eye cannot be freely moved in that direction during the test, giving a positive result. If there were no mechanical barrier, the forced duction would be negative, pointing toward a neurogenic or other non-mechanical cause of restriction. Therefore, orbital floor fractures are most likely associated with a positive forced duction test.

The key idea is distinguishing mechanical restriction from nerve or muscle weakness using the forced duction test. A positive forced duction test means there is a physical barrier preventing the eye from moving when the examiner tries to move it passively—you feel resistance. In orbital floor (blow-out) fractures, the inferior rectus muscle or orbital tissue can become trapped in the fracture site, creating a mechanical tether. This entrapment restricts movement, especially upward gaze, so the eye cannot be freely moved in that direction during the test, giving a positive result. If there were no mechanical barrier, the forced duction would be negative, pointing toward a neurogenic or other non-mechanical cause of restriction. Therefore, orbital floor fractures are most likely associated with a positive forced duction test.

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