93Following successful performance of a right interscalene block for surgical rotator cuff repair in a 27-yearold patient with no other medical issues, you are called to the recovery room (post–anesthesia care unit) 3hours later to evaluate the patient. The patient’s symptoms include drooping of the right eyelid, redness ofthe conjunctiva, and pupillary constriction. The most likely diagnosis is
(A) Spinal anesthesia
(B) Subdural injection of local anesthetic
(C) Horner syndrome
(D) Cerebrovascular accident (CVA)