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عدم استجابة المنعكس الحدقي للضوء Unresponsive pupillary light reflex


عدم استجابة المنعكس الحدقي للضوء Unresponsive pupillary light reflex

يوضح هذا النموذج كيف أن الحدقة اليمنى لا تستجيب للضوء بينما الحدقة اليسرى تبدي استجابة...
علماً أنه عندما نوجه الضوء على إحداهما يجب على الأخرى أن تبدي نفس الاستجابة أيضاً...

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شكرا بيرلز 2 Razz

qusei


روعة pearls-2

يسلمو هالايدين

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a.m.a
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شكرا

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mbs2380
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mbs2380's picture
mbs2380
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Quote:

Diff. Dx

ok lets remember first ..
that the afferent will arise on light stimulus from optic nerve
then reaches pretectal nucleus in superior colliculus in mid brain giving rise to CNIII oculomotor fibers from EW nucleus after relaying in ciliary ganglion

lets see now

if i cut the oculomotor nerve of the right side

right direct eye light reflex will be lost cuz rt optic will signal but no response cuz rt CNIII wont stimulate constrictor pupilae

consensual left eye relfex will be intact cuz the signalling right optic will try to stimulate both left and right oculomotor , but the right CNIII is cut so wont respond but left CNIII is still intact so the left eye will constrict

same goes to rest

left direct eye light reflex will b intact cuz left optic and CNII are normal

but consensual right eye reflex will be lost again cuz rt CNIII is cut


now u tell me wat will happen if we cut the optic nerve on the right side for ex ?


--------

about differential diagnosis , for ex. maybe there is a leison in the mid brain affecting the pretectal nuclues and consequently CNIII

maybe there is increased ICP ( tumors , abcess , aneurysm , hydrocephlus ,etc...) causing compression on the optic nerve since its covered by a sheath of subarachnoid

any cause harming oculomotor or optic nerve can damage the pupillary light reflex

but here .. its right oculomotor nerve injury

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