How does cervical artery dissection develop?

How does cervical artery dissection develop?

Cervical artery dissection begins as a tear in one layer of the artery wall. Blood leaks through this tear and spreads between the layers of the wall. As the blood collects in the area of the dissection, it forms a clot that limits blood flow through the artery. If the clot is large enough to completely block blood flow, this can result in a stroke. Equally dangerous, pieces of the clot can break off and travel up through the bloodstream, limit the blood flow to the brain and cause a stroke.

Depending on where the dissection occurs in the artery, it may cause the artery to bulge in the area where the blood is pooling. This bulging, blood-filled area is called a pseudoaneurysm. If within the brain, these can be fragile and carry a risk of breaking and causing bleeding around the brain (called a subarachnoid hemorrhage); however if in the neck, these rarely break, though they may produce symptoms by pressing on surrounding structures. Sometimes pseudoaneurysms can form after the initial artery dissection.