Introduction to Ocular Motility Extraocular Muscles EOM ...

Ductions and Versions
Versions - Movement of both eyes
Amplitude, smoothness, palpebral fissure
height, pupil size, oscillations.
Ductions – Movement of one eye
If versions abnormal
Improvement on ductions suggests
paretic process
Normal Versions
Normal Versions
Herring’s Law of Equal
Innervation
When an impulse goes to a muscle to
contract, an equal impulse goes to it’s
contralateral synergist (yoke muscle).
Sherrington’s Law of
Reciprocal Innervation
When an impulse goes to a muscle to
contract, an equal and opposite
impulse to relax goes to it’s ipsilateral
antagonist.
CN VI palsy (LR)
Limitation of abduction
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