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: ENT
[{'content': 'Facial nerve palsy at sternomastoid canal can cause- \nSelect and explain. \nA. Loss of corneal reflex at side of lesion, B. Loss of taste sensation anterior 2/3 of ipsilateral tongue, C. Loss of lacrimation at side of lesion, D. Hyperacusis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Below stylomastoid foramen, facial nerve gives following branches: - Posterior auricular branch, muscular branches (stylohyoid & posterior belly of digastric) and terminal (peripheral) branches.\nLesion at sternomastoid foramen : -\n\ni)\xa0\xa0\xa0 Will spare\n\nGreater superficial petrosal nerve → Lacrimation present.\nNerve to stapedius → Normal stapedial reflex and no hyperacusis.\nChorda tympani → Normal salivation and a taste sensation in anterior 2/3 of the tongue.\n\nii) Will involve\n\nTerminal (peripheral) branches → Paralysis of muscles of facial expression. Corneal reflex will also be lost because efferent fibres of corneal reflex are derived from peripheral branches of the facial nerve.', 'role': 'assistant'}]