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
A patient present with enophthalmos after a trauma to face by blunt object.There is no fever and no extraocular muscle palsy. Diagnosis is: 
Select and explain. 
A. Fracture maxilla, B. Fracture zygoma, C. Blow out fracture, D. Fracture ethmoid
C: Blow out fracture
Answer: C: Blow out fracture 
Explanation: Blow out fracture is isolated fracture of orbital floor, when a large blunt object strikes the globe. It presents with:Ecchymosis of lid, conjunctiva and scleraEnophthalmosDiplopia due to displacement of eye ballAnaesth esia of cheek and upper lip, if infraorbital nerve is involved.