Aortic Arch

The aortic arch is the second portion of the thoracic aorta. It follows the ascending aorta and is extended by the descending aorta, at the level of the 4th thoracic vertebra (T4). Located in the mediastinum, it begins at the upper edge of the second right sternocostal joint. It turns to travel upwards, backwards and to the left, in front of the trachea. It then turns backwards, passing over the left side of the trachea, and finally descends over the left edge of the trachea, and from the left edge of the vertebrae to the body of the fourth thoracic vertebra, where it continues along the descending aorta. It thus forms two curves:one convex upwards (to bypass the root of the left lung);the other convex forwards and to the left (to bypass the trachea and oesophagus).its upper edge is usually about 2.5 cm below the upper edge of the sternal manubrium.