“…Horner's syndrome (HS) is a result of the interruption of sympathetic innervation to ocular structures and is characterized by ipsilateral miosis, facial anhidrosis, enophthalmos, conjunctival injection, and facial flushing [ 1 , 2 ]. HS has been reported in connection with various regional anesthetic techniques, such as those involving the brachial plexus, cervical plexus, paravertebral, and epidural blockade [ 2 , 3 ]. This syndrome is associated with the blockade of oculosympathetic fibers, which occurs at the point where preganglionic neurons exit the spinal cord and then ascend through the sympathetic chain to reach the superior cervical ganglion [ 2 ].…”