Corneal Reflex: Anatomy

Basic, Organ-Based and Clinical Sciences

Corneal reflex: afferent = V1 branch of trigeminal nerve, efferent = facial nerve

Steps:

Pain receptors in cornea detect an irritating stimulus

C fibers are activated

Signal travels to cell bodies of C fibers in trigeminal ganglion, then via trigeminal sensory root à spinal trigeminal tract à spinal trigeminal nucleus of the pars caudalis

Pars caudalis neurons cross midline and branches into two routes

  1. Branches to bilateral facial motor nuclei à facial nerve à through the stylomastoid foramen à zygomatic branch of facial nerve à orbicularis oculi muscle à close bilateral eyelids

  2. Ascending anterior trigeminothalamic fibers à ventral posteromedial thalamic nucleus à recognition of painful stimulus

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Answered correctly

2019

Year asked

Author
Stephanie Caldwell, MD