A 55-year old man complained of right-sided weakness, especially the lower limb. When he stood up, he fell down due to weakness of the right leg. The condition lasted for about 24 hours after which he had complete recovery from the symptoms. Deeply concerned of the episode, he sought medical consultation. He was diagnosed to have had a transient ischemic attack (TIA). A duplex Doppler scan of the carotid arteries was done and revealed significant stenosis of the left internal carotid artery near the bifurcation of the common carotid artery. What is a transient ischemic attack? In the case of this patient, what could have caused it? Why is it common to have stenosis of arteries in areas where they bifurcate? What are other contributory factors to arterial stenosis?