Cavernous Sinus

Which of the following cranial nerves does NOT pass through the cavernous sinus?

Which anatomical feature best distinguishes thrombosis of the cavernous sinus from orbital cellulitis?

A 38-year-old woman from Mumbai presents with fever, severe bilateral periorbital edema, and chemosis for 3 days. She has a history of untreated sinusitis. On examination, she has bilateral ptosis, restricted eye movements in all directions, and bilateral ophthalmoplegia. Her pupils are dilated and unreactive. Blood cultures grow Staphylococcus aureus. CT brain shows bilateral cavernous sinus enhancement with thrombosis. Which of the following anatomical features explains why infection can spread rapidly from the paranasal sinuses to the cavernous sinus?

A 42-year-old woman from Mumbai presents with 3 days of progressive right eye pain, vision loss, and chemosis. Examination reveals proptosis, ophthalmoplegia (CN III and VI), and a dilated fixed pupil. Temperature is 37.2°C (afebrile). MRI shows a mass in the right cavernous sinus with enhancement. Serum ACE level is elevated. What is the most appropriate next step in management?

A 32-year-old man presents with fever, periorbital edema, proptosis, and ophthalmoplegia following a boil on his upper lip. Blood cultures grow Staphylococcus aureus. What is the most common primary source of infection in cavernous sinus thrombophlebitis in this clinical context?