in the cavernous sinus obstruction, also known as a sinus thrombosis Formed in the cavernous sinus Cavernous sinus is the ventricle at the bottom of the brain in the skull. It drains blood from the brain and the middle of the face back to the heart. Cranial nerves surround the sinus. These nerves are needed for eye movement and sensation in the upper and middle parts of the head and face. People of any age, gender, or race can have this condition.