Horner's syndrome (miosis, ptosis, anhidrosis) results from interruption of sympathetic pathways. A lesion of the first-order neuron (central pathway) would be located in:
- A Ciliospinal centre of Budge (C8–T2 intermediolateral column)
- B Superior cervical ganglion
- C Long ciliary nerves on the surface of the internal carotid artery
- D Hypothalamus to ciliospinal centre descending ipsilateral pathway ✓
Explanation
The sympathetic pathway to the eye has three neurons. The first-order neuron runs from the ipsilateral posterior hypothalamus, descending through the brainstem tegmentum and spinal cord to synapse at the ciliospinal centre of Budge (C8–T2). The second-order (preganglionic) neuron exits the spinal cord and synapses in the superior cervical ganglion. The third-order (postganglionic) neuron travels with the internal carotid artery to the eye. A first-order lesion (hypothalamus to ciliospinal centre) is commonly caused by brainstem stroke, syringomyelia, or cervical cord disease. The ciliospinal centre (Budge) is the second-order neuron's origin, not the first.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
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Written and medically reviewed by the StethoPrep medical team.