So diplopia (and any nystagmus) will be ellicited and maximal when the patient's affected eye is adducted and then asked to look down ... The two images (real and false) will be orientated obliquely to one another ... Unlike the two parallel images in a lateral rectus/abducens lesion.
There is some confusion out there regarding testing the trochlear nerve and isolating the position where a patient with a trochlear nerve lesion will have diplopia and likely nystagmus ... This is the explanation right here. Only when the eye is adducted (turned in towards the nose) does the superior oblique act as almost a pure depressor of the eyeball ... In the neutral or straight ahead position the principle action of the superior oblique is intortion ...
A really nice explanation with a good visualisation! Well done! Thanks
miguelj86 3 weeks ago
So diplopia (and any nystagmus) will be ellicited and maximal when the patient's affected eye is adducted and then asked to look down ... The two images (real and false) will be orientated obliquely to one another ... Unlike the two parallel images in a lateral rectus/abducens lesion.
DoctorCallan 7 months ago
There is some confusion out there regarding testing the trochlear nerve and isolating the position where a patient with a trochlear nerve lesion will have diplopia and likely nystagmus ... This is the explanation right here. Only when the eye is adducted (turned in towards the nose) does the superior oblique act as almost a pure depressor of the eyeball ... In the neutral or straight ahead position the principle action of the superior oblique is intortion ...
DoctorCallan 7 months ago
does make sense
ivinsha91 7 months ago