Vertebrobasilar insufficiency is a condition characterized by poor blood flow to the posterior (back) portion of the brain, which is fed by two vertebral arteries that join to become the basilar artery. Blockage of these arteries occurs over time through a process called atherosclerosis, or the build-up of plaque.
No, Portugal is not a Mediterranean country. It does, however, have a mediterranean climate, but it is not considered a mediterranean country because the south does not have the Mediterranean Sea as a coast.
The Mediterranean Sea is connected to the Atlantic Ocean by a narrow passage called the Strait of Gibraltar. It is between the southern tip of Spain and northern Morroco.