Intercavernous sinuses

The intercavernous sinuses are two in number, an anterior and a posterior, and connect the two cavernous sinuses across the middle line.

The anterior passes in front of the hypophysis cerebri, the posterior behind it, and they form with the cavernous sinuses a venous circle (circular sinus) around the hypophysis.

The anterior one is usually the larger of the two, and one or other is occasionally absent.