This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': "Injury to cervical sympathetic trunk produces Horner's syndrome that includes all except: \nSelect and explain. \nA. Enophthalmos, B. Ptosis, C. Mydriasis, D. Anhydrosis", 'role': 'user'}, {'content': "Answer: C \nExplanation: Horner’s syndrome:\xa0\nThe head and neck region is supplied by the sympathetic fibres, which arise in the upper thoracic spinal segments.\xa0\nThese preganglionic fibres pass through stellate ganglion to relay in the superior cervical sympathetic\nganglion.\xa0\nThe postganglionic fibres arise from cells of this ganglion and supply the structures in the head and neck.\nAn injury to cervical sympathetic trunk produces a clinical condition called Horner’s syndrome.\nCharacteristic features:\n\nPartial ptosis (partial drooping of upper eyelid), due to paralysis of smooth part of levator palpebrae superioris muscle (Muller’s muscle).\nMiosis, i.e., constriction of the pupil, due to paralysis of dilator pupillae.\nAnhydrosis, i.e., loss of sweating on that side of face, due to sudomotor and vasoconstrictor denervation.\nIncreased temperature and redness.\nEnophthalmos, i.e., sunken eyeball, not confirmed by ophthalmometry.\nLoss of ciliospinal reflex, i.e., pinching the skin of the back of neck does not produce dilation of the pupil, which in healthy person takes place.\n\n\nKey Concept:\nInjury to cervical sympathetic trunk produces Horner's syndrome that includes Enopthalmos, Ptosis and miosis.\nRef: Textbook of Anatomy, Vishram singh, pg no:175", 'role': 'assistant'}]