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: Anatomy
Cavernous sinus thrombosis is due infection of 
Select and explain. 
A. Pterygoid plexus, B. Submental space, C. Maxillary sinus, D. Submandibular space
A: Pterygoid plexus
Answer: A: Pterygoid plexus 
Explanation: Pterygoid plexus and the facial vein form the 2 major sources which carry the infections from the danger area of face to the cavernous sinus.