You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Supranuclear lesion of facial nerve affects and explain in detail?
It is caused by cerebrovascular accidents (haemorrhage, thrombosis or embolism), tumour or an abscess. It causes paralysis of only the lower half of face on the contralateral side. Forehead movements are retained due to bilateral innervation of frontalis muscle. Involuntary emotional movements and the tone of facial muscles are also retained. Ref: Dhingra 7e pg 107.