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: Orthopaedics
[{'content': 'A 30-year-Old male underwent excision of the right radial head. Following surgery, the patient developed an inability to extend the fingers and thumb of the right hand. He did not have any sensory deficit. Which one of the following is the most likely cause? \nSelect and explain. \nA. Injury to Posterior interosseus nerve, B. latrogenic injury to common extensor origin, C. Injury to anterior interosseus nerve, D. High radial nerve palsy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Clinical features of radial nerve palsy \n\nClinical features depend upon the site of the lesion.\n\n1) 1f lesion is high\n\nWrist drop, thumb drop and finger drop.\nInability to extend elbow, wrist, thumb & fingers (MP joint)\nThe patient can extend interphalangeal joints due to the action of lubricants and interossei.\nSensory loss over posterior surface of arm & forearm and lower lateral half of forearm.\n\n2) If the lesion is low\na) Type I\n\n\nWrist drop, thumb drop and finger drop.\nElbow extension is preserved.\nSensory loss over the dorsum of first web space.\n\nb)\xa0Type II\n\nThumb drop and finger drop\nElbow and wrist extension is preserved\nSensory loss over the dorsum of first web space\n\nClinical features of posterior interosseous nerve\n\nIt is prone to be injured in injury & operations of radial head- neck.\nThere is no sensory deficit as it is a pure motor nerve.\nWrist extension is preserved (i.e. no wrist drop) due to spared extensor carpi radialis longus .\nPresents with loss of extension of metacarpophalangeal (MP) joints i.e., thumb & finger drop.', 'role': 'assistant'}]