Re: Q1

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Posted by Veronica from IP on October 21, 2013 at 23:18:40:

In Reply to: Q1 posted by Veronica on October 09, 2013 at 16:13:47:

I try to post the qs that I was sure I did right, but I was wrong. Like this one I thought it was T1, as Horner's syndrome involves T1, but here is the explanations


The presence of ptosis and myosis indicate oculosympathetic palsy - Horner's syndrome. This indicates the injury to the sympathetic supply to the eye. This pathway begins in the
hypothalamus, travels down through the lateral aspect of the brain stem, synapses in the intermediolateral cell column of the spinal cord, exits the spinal cord at the level of T1 and
synapses again in the sup. cervical ganglion. From here postganglionic fibers travel along the surface of the common carotid and internal carotid artery until branches leave along the
ophthalmic artery to the eye. The disease, involving internal carotid artery and the overlying sympathetic plexus do not produce anhydrosis, the 3-d element of Horner's syndrome. In this
case, the occurrence of painful Horner's syndrome occurring after vigorous activity is virtually diagnostic of carotid artery dissection. Dissections may occur more frequently in migraineurs

Lesions of cranial nerve III do cause ptosis, but they would also be expected to cause ipsilateral midriasis. The degree of ptosis is much more severe in III nerve palsy, than in Horner's, this
is because III supplies the levator palpebrae (primary levator of the lid), whereas the sympathetics supply Muller's muscle, (accessory role).
The sympathetic pathway does exit the spinal cord at T1, but injury at his location would not cause orbital pain, which is typical of carotid arterial dissection

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