Cavernous sinus thrombosis can spread from facial skin infections because of communication with facial veins. The cavernous sinus communicates directly with the facial vein via which venous route?

• A Inferior ophthalmic vein → inferior orbital fissure → pterygoid plexus → facial vein
• B Inferior petrosal sinus → internal jugular vein → common facial vein
• C Sphenoparietal sinus → middle meningeal vein → external jugular vein
• D Superior ophthalmic vein → angular vein → facial vein (valveless, allowing retrograde flow) ✓

Explanation

The dangerous area of the face drains via the facial (angular) vein, which is valveless. The angular vein at the medial canthus communicates directly with the superior ophthalmic vein, which drains posteriorly into the cavernous sinus via the superior orbital fissure. Because these veins lack valves, thrombophlebitis from facial skin infections (furuncles of the nose, upper lip) can propagate retrograde into the cavernous sinus, causing cavernous sinus thrombosis. The inferior ophthalmic vein additionally communicates with the pterygoid plexus, which connects to the cavernous sinus via emissary veins.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.