A positive forced duction test indicates what in the setting of orbital injury?

A positive forced duction test indicates what in the setting of orbital injury?

• A. Neurological Palsy
• B. Conjugate Movement Failure
• C. Sympathetic Blockade
• D. Mechanical Restriction Due To Entrapment

Answer: (D)

The key idea is that the forced duction test tells you whether the eye’s movement limitation is due to a physical blockage or to a neural/muscle weakness. A positive result means there is resistance to passive movement of the globe, indicating a mechanical restriction—usually entrapment of a muscle or tissue after orbital trauma. In this setting, entrapment from a blowout fracture commonly tightens the muscle against the orbital rim, restricting movement and causing diplopia. If the movement could be passively moved without resistance, the problem would be neurogenic or myopathic rather than mechanical, which is why those other scenarios don’t fit a positive forced duction.

The key idea is that the forced duction test tells you whether the eye’s movement limitation is due to a physical blockage or to a neural/muscle weakness. A positive result means there is resistance to passive movement of the globe, indicating a mechanical restriction—usually entrapment of a muscle or tissue after orbital trauma. In this setting, entrapment from a blowout fracture commonly tightens the muscle against the orbital rim, restricting movement and causing diplopia. If the movement could be passively moved without resistance, the problem would be neurogenic or myopathic rather than mechanical, which is why those other scenarios don’t fit a positive forced duction.