A patient with an aneurysm of the internal carotid artery in the cavernous sinus develops ipsilateral pulsatile exophthalmos and a bruit over the orbit. Which vein communicates with the cavernous sinus and becomes engorged?

• A Retromandibular vein
• B Facial vein
• C Superior ophthalmic vein ✓
• D Lingual vein

Explanation

In carotid-cavernous fistula or aneurysm, arterial blood flows into the cavernous sinus, increasing pressure in it. The superior ophthalmic vein drains into the cavernous sinus and becomes engorged, causing pulsatile exophthalmos, chemosis, and conjunctival congestion. The facial vein also connects indirectly but the superior ophthalmic vein is the direct drainage and the primary cause of the orbital signs.

Reference: Gray's Anatomy, 42nd ed.

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Written and medically reviewed by the StethoPrep medical team.