What are the signs and symptoms of trochlear nerve palsy (fourth nerve palsy)?

Updated: Oct 08, 2019
  • Author: Zafar A Sheik, MD, MD; Chief Editor: Andrew G Lee, MD  more...
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The superior oblique muscle intorts, depresses, and abducts the globe.

In acquired lesions of fourth nerve, patients report vertical, torsional, or oblique diplopia. Diplopia is usually worse on downgaze and gaze away from side of affected muscle.

In case of trauma, patients usually report symptoms immediately after regaining consciousness.

Torsional diplopia and downgaze horizontal diplopia may be predominant complaints in bilateral palsies. [17]

Patients may adopt a characteristic head tilt, away from affected side to reduce their diplopia. Interestingly, some patients develop head tilt toward side of lesion. This so-called paradoxic head tilt is used to create a wider separation of images, which allows the patient to suppress or ignore one image. Old photographs may provide clear documentation of a head tilt in congenital fourth nerve palsy.

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