sternal line of pleural reflection

sternal line of pleural reflection

surface projection of the sharp line along which the costal part of the parietal pleura becomes continuous with the mediastinal part anteriorly; the right and left sternal lines of pleural reflection are parallel to the median plane, posterior to the sternum, at the level of costal cartilages 2-4; at the level of costal cartilage 4, the left line turns laterally to parallel the left margin of the sternum, creating a "notch" that is shallower than the cardiac notch of the left lung and an area where the pericardial sac contacts the anterior thoracic wall without intervening pleura sac, a finding significant for pericardiocentesis.