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: Radiology
[{'content': 'The radiopaque structure shown in the box is most likely: \nSelect and explain. \nA. Lingual foramen, B. Genial tubercle, C. PCD, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The genial tubercles (also called the mental spine) are located on\xa0the\xa0lingual\xa0surface\xa0of\xa0the\xa0mandible\xa0slightly\xa0above\xa0the\xa0inferior\xa0border and in the midline. They are bony protuberances, more or less spine-shaped, that often are divided into a right and left prominence\xa0and\xa0a\xa0superior\xa0and\xa0inferior\xa0prominence.\xa0\nThey\xa0attach\xa0the genioglossus muscles (at the superior tubercles) and the geniohyoid\xa0muscles (at the inferior tubercles) to the mandible. They are well\xa0visualized\xa0on\xa0mandibular\xa0occlusal\xa0radiographs\xa0as\xa0one\xa0or\xa0more\xa0small projections. Their appearance on periapical radiographs\xa0of the\xa0mandibular\xa0incisor\xa0region\xa0is\xa0variable;\xa0often\xa0they\xa0appear\xa0as\xa0a\xa0radiopaque\xa0mass\xa0(3\xa0to\xa04 mm\xa0in\xa0diameter)\xa0in\xa0the\xa0midline below the incisor roots.\xa0Lingual foramen is a radiolucent structure seen in the midline.\nRef: White and Pharoah, pg-144,145', 'role': 'assistant'}]