Your arteries are pliable tubes with thick, elastic walls. Oxygenated blood leaves your heart through your body's main artery, the aorta. The aorta then subdivides into smaller arteries that deliver blood to all parts of your body, including your brain and internal organs.

With giant cell arteritis, some of these arteries become inflamed, causing them to swell and sometimes decreasing blood flow. Just what causes these arteries to become inflamed isn't known.

Although almost any large or medium-sized artery can be affected, swelling most often occurs in the temporal arteries in your head, which are located just in front of your ears and continue up into your scalp. In some cases, the swelling affects just part of an artery with sections of normal vessel in between.

Oct. 05, 2012