E-Pearl of the Week: The ciliospinal reflex

October 17, 2012


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October 16, 2012

The ciliospinal reflex

The ciliospinal reflex (CSR) is a test of ocular sympathetic function and consists of a rapid bilateral pupillary dilation elicited by a pinch to the face, neck, or upper trunk [1, 2]. It is more pronounced in sleep and in comatose patients. The reflex is most often tested in the evaluation of suspected Horners syndrome  and brain death, where the reflex is expected to be absent. The CSR may, however, be preserved in cases of first-order Horners syndrome, rostral brain stem lesions, and brain death when the noxious stimulus is applied to the neck or trunk, due to local activation of second-order sympathetic efferents from the ciliospinal center of Budge (C8-T2).


  1. Reeves AG, Posner JB. The ciliospinal response in man. Neurology 1969;19; 1145-1152.
  2. Ikeda H, Aruga T, Hayashi M, Miyake Y, Sugimoto K, Mastumoto K. Two cases in which the presence of ciliospinal response led to indecisiveness in the evaluation of brain death. No To Shinkei. 1999; 51: 161-166.

Submitted by: Garth Turner, MD

Disclosure: Dr. Turner report no disclosures.

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