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: Surgery
[{'content': 'While giving IANB nerve block, postoperatively the patient complains of trismus due to: \nSelect and explain. \nA. Injection into buccinator, B. Injection into parotid capsule, C. Injection into medial pterygoid, D. Paralysis of nerve', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Trismus is inability to open mouth due to muscle spasm. It is caused by injection into medial pterygoid muscle resulting in hematoma formation or infection. The application of heat and administration of antibiotics relieve the symptoms.', 'role': 'assistant'}]