Sternal angle corresponds to:

Sternal angleIt varies around 162 degrees in malesIt marks the approximate level of the 2nd pair of costal cailages, which attach to the second ribs, and the level of the interveebral disc between T4 and T5.The angle also marks a number of other features:-- Boundary between the superior and inferior poion of the mediastinumPassage of the thoracic duct from right to left behind esophagus- Aoic Arch- Tracheal Bifurcation- End of the azygos system into SVC- Ligamentum aeriosum- Loop of left recurrent laryngeal nerve around aoic arch- Aoic arch stas and ends