SECTION EDITOR: BENNIE H. JENG, MD
Horner syndrome secondary to subclavian artery aneurysm
D. Neck MRI/magnetic resonance angiography without contrast
Horner syndrome is caused by interruption of sympathetic innervation to the eye and ocular adnexa, producing ipsilateral ptosis, miosis, and anhidrosis. Interruption of the pathway can occur anywhere along the sympathetic chain, including the first-order (central) neuron descending from the hypothalamus to brainstem, the second-order (preganglionic) neuron exiting the spinal cord and ascending in the sympathetic chain through the region of the lung apex, or the third-order (postganglionic) neuron traveling with the internal carotid artery, through the cavernous sinus, and into the orbit.
Twenty-four–Year-Old Woman With a Droopy Eyelid—Diagnosis. JAMA Ophthalmol. 2013;131(3):402. doi:10.1001/jamaophthalmol.2013.52b