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: Unknown
[{'content': 'Hanging drop sign in x-ray is seen in - \nSelect and explain. \nA. Orbital floor fracture, B. Medial wall fracture, C. Lateral wall fracture, D. Superior margin fracture', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (Orbital floor fracture) Ref: AK Khurana, 4th ed, p. 398Hanging drop sign in roentgenogram is seen in orbital floor fracture.Orbital floor fractureThe most useful projection for detecting orbital floor fracture is waters view:Findings in x-ray include:Fragmentation and irregularity of orbital floorDepression of bony fragments"Hanging drop" opacity in the superior maxillary antrum. It is due to the herniation of orbital contents through the floor.', 'role': 'assistant'}]