USMLE QUESTION OF THE DAY

Zygomycosis, a destructive fungal infection of the sinuses, is likely to
reach the brain by which of the following routes?

Correct

The correct answer is A. The cavernous sinuses are located on either side of the body of the sphenoid bone, and become a potential route of infection because they receive blood both from the face (via the ophthalmic veins and sphenoparietal sinus) and some of the cerebral veins. The spread of infection, especially by Mucor sp., into the cavernous sinus, can produce either CNS infection or cavernous sinus thrombosis, both of which are potentially fatal.
The route from the face to the brain is not arterial (choices B and C).
The superior sagittal sinus (choice D) is located in the falx cerebri, and drains venous blood from the brain to other dural sinuses, from which it eventually drains into the jugular vein. Zygomycosis does not reach the brain by way of the superior sagittal sinus.
The superior vena cava (choice E) drains blood from the upper part of the body into the heart.

Incorrect

The correct answer is A. The cavernous sinuses are located on either side of the body of the sphenoid bone, and become a potential route of infection because they receive blood both from the face (via the ophthalmic veins and sphenoparietal sinus) and some of the cerebral veins. The spread of infection, especially by Mucor sp., into the cavernous sinus, can produce either CNS infection or cavernous sinus thrombosis, both of which are potentially fatal.
The route from the face to the brain is not arterial (choices B and C).
The superior sagittal sinus (choice D) is located in the falx cerebri, and drains venous blood from the brain to other dural sinuses, from which it eventually drains into the jugular vein. Zygomycosis does not reach the brain by way of the superior sagittal sinus.
The superior vena cava (choice E) drains blood from the upper part of the body into the heart.