A dissection is a tear of an artery that allows blood to spill or leak out of the blood vessels and inserts itself directly into the blood vessel wall. The blood courses between layers of the vessel wall, separating the tissues that form the lining of the artery. This results in a hematoma or an aneurysm of the blood vessel wall. Both processes create thrombi, emboli, narrowing of the vessel, and pressure against surrounding structures. As such, the dissection of the carotid artery is a cause of ischemic stroke. The dissection usually stops spontaneously.
The incidence of symptomatic spontaneous internal carotid artery dissection is estimated to be approximately 3 per 100,000, although the actual incidence may be higher because some dissections are asymptomatic or remain undiagnosed. Carotid artery dissection is usually spontaneous, but some result from blunt trauma. At times, there is a precipitating event such as sports injuries or direct manipulation of...