![]() The preganglionic (second-order) neuron then travels up the sympathetic chain, over the lung apex and through several ganglia to synapse at the superior cervical ganglion, located where the carotid bifurcates. The sympathetic central (first-order) neuron begins in the dorsolateral hypothalamus and travels, uncrossed, through the brainstem to the ciliospinal center of Budge at the level of C8 to T2 in the cervical spinal cord. Sympathetic innervation to the eye involves a three-neuron chain. Postganglionic parasympathetic pupillary fibers travel along the short ciliary nerves to the ciliary body muscle (93% to 97% of fibers) and to the circumferential iris sphincter (3% to 7% of fibers). The fibers then travel in the superficial layer of the third cranial nerve to the cavernous sinus, follow the cranial nerve’s inferior division through the superior orbital fissure and synapse in the ciliary ganglion, which is posterior to the globe, within the muscle cone. The parasympathetic efferent pupillary pathway begins where the afferent pathway left off: the Edinger-Westphal nucleus. The efferent (motor) pupillary pathway has both parasympathetic and sympathetic nervous system actions. The consensual light reflex occurs because both the optic and tectotegmental tracts carry fibers from both eyes. They then leave the pretectal nucleus and distribute about equally to the two Edinger-Westphal nuclei via the tectotegmental tract. From there, they travel to the midbrain and synapse at the pretectal nucleus, at the level of the superior colliculus. The neural fibers separate from the tract just anterior to the lateral geniculate body. The afferent (sensory) pupillary pathway begins with the retinal photoreceptors, passes through the optic nerve and optic chiasm and travels along the posterior third of the optic tract. ![]() Having an understanding of the neural pathways that control the normal afferent and efferent pupillary responses is foundational, so we will review this before discussing abnormalities of the pupillary response. The pupils will offer substantial insight into one’s ocular health and the state of the visual pathways before even looking into a patient’s eyes. The keen practitioner can gain helpful information simply by assessing pupillary responses. If you continue to have this issue please contact to Healio We look forward to resuming business as usual in the coming weeks and wish you all health and safety during this time.We were unable to process your request. We appreciate your understanding as we expand flexible work settings, hours, and service offerings This is a challenging time for all of us and we are doing everything we can to protect the Oregon Rule Co. community and are still offering the following services though some may have small delays:Ĭustomer Service is available during normal business hours to assist with any questions you may have.Ī smaller team remains on-site to prepare and ship your orders. While difficult and unprecedented, we are doing our best to minimize the impact to our external Oregon Rule Co. This is an important step to support our community's response to help flatten the curve. will be proactively limiting on-site operations Monday, March 30th. It is our responsibility to stay vigilant and do our part to help our community come out of this stronger.Īfter careful consideration, Oregon Rule Co. ![]() The health and safety of our employees, their families, and our community remains our top priority.
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