The ciliospinal reflex involves the dilation of the ipsilateral pupil in response to painful stimulation applied to the neck, face, or upper trunk. This reflex is mediated by the sympathetic nervous system, which activates the dilator pupillae muscle of the eye.
Mechanism of the Ciliospinal Reflex
Painful stimulus on the neck, face, or upper trunk triggers a response in the sympathetic nervous system.
The signal travels via afferent fibers to the spinal cord, where it activates sympathetic efferent fibers.
These sympathetic fibers cause pupil dilation on the same side as the stimulation.
