Ciliospinal

Ciliospinal refers to a neural pathway and the associated cluster of neurons involved in the sympathetic innervation of the head and neck. The ciliospinal center of Budge is a group of preganglionic sympathetic neurons located in the intermediolateral cell column of the spinal cord, specifically in segments C8 through T2.

Preganglionic fibers from this region exit the spinal cord via the ventral roots and travel through the sympathetic chain to the superior cervical ganglion, where they synapse. Postganglionic fibers then reach targets such as the iris dilator muscle, facial vasculature, and sweat glands, contributing to pupil dilation and other facial sympathetic responses. The term also relates to the ciliospinal reflex, a pupil dilation response elicited by stimulation of the neck, which engages the same sympathetic pathways.

Clinically, disruption of the ciliospinal pathway can occur with conditions affecting the sympathetic chain, most notably Horner's syndrome. This syndrome presents with ptosis, miosis, and anhidrosis on the affected side and may reduce or abolish the ciliospinal reflex on that side.

The ciliospinal center of Budge is named after its historical description in neuroanatomy, and the term ciliospinal is used to describe both the anatomical center and the reflex pathway that links cervical (neck) input to eye and facial sympathetic outputs.