A 65-year-old patient has a unilateral slowly enlarging mass at the vertex of the skull producing hyperostosis on CT. The most likely meningioma variant is parasagittal. Through which venous sinus does the meningioma spread intracranially to cause venous hypertension?

• A Superior sagittal sinus — the parasagittal meningioma invades the sinus causing venous obstruction and raised ICP ✓
• B Inferior sagittal sinus — runs in the free border of the falx cerebri
• C Transverse sinus — runs along the posterior fossa tentorium
• D Straight sinus — drains the great cerebral vein

Explanation

Parasagittal meningiomas arise from the arachnoid cap cells along the walls of the superior sagittal sinus (SSS). The SSS runs in the attached (upper) border of the falx cerebri from the crista galli to the occipital protuberance. These tumours can invade the SSS lumen, causing venous thrombosis, raised ICP, and bilateral lower limb weakness (due to compression of the paracentral lobules — the area of motor cortex for the legs). The inferior sagittal sinus runs in the free (lower) border of the falx. The straight sinus receives the great cerebral vein (of Galen). The confluence of sinuses (torcula Herophili) receives the SSS, straight sinus, and connects to transverse sinuses.

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

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Written and medically reviewed by the StethoPrep medical team.