Transient ischemic attack (TIA for short) is caused by the subclavian steal syndrome, a direct consequence of Bernoulli's Principle. TIA is simply a temporary shortage of blood to the brain. This can be easily explained if we look at the path bloot takes to get to the brain. it comes through two arteries on opposite sides of the neck, joining at the Basilar artery, which goes to the brain. These two arteries are known as the subclavian arteries. The problem arises if one of them is partially blocked. When this happens, the other artery must pick up the slack, increasing the velocity of the blood there. This creates an imbalance of pressure -- the pressure of the slacker artery is lower than its cousin. The consequence of this is that some of the blood from the good artery will go into the slacker artery instead, as per Bernoulli's Principle, hence the subclavian steal -- one of the subclavians steals blood from the other. Another mystery explained away by simply Physics.