Normal PA film of a male. Note the right and left clavicles (cl), posterior (p1-4) and anterior (a1-2) ribs, right and left costophrenic angles(cpa), right cardiophrenic angles (cdpa), right and left hemidiaphragms (hd), gastric air bubble (gab), trachea (tr), right and left mainstem bronchi (br), mediastinal shadow (med), carina (ca), and right and left hila (hi). The normal position of the minor fissure (mi) is also indicated.