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: ENT
Mucocele is commonly seen in sinus: 
Select and explain. 
A. Frontal, B. Maxillary, C. Ethmoid, D. Sphenoid
A: Frontal
Answer: A: Frontal 
Explanation: A mucocele is an epithelial lined, mucus containing sac completely filling the sinus and capable of expansion: Mucocele are most commonly formed in Frontal sinus followed by ethmoid, sphenoid and maxillary sinuses. Mucocele of frontal sinus presents as a swelling in the floor of frontal sinus above the inner (medial) canthus. It displaces the eyeball forward, downward and laterally. IOC = CT scan TOC Endoscopic sinus surgery