Anterior border of lung

The anterior border of the lung is thin and sharp, and overlaps the front of the pericardium.

The anterior border of the right lung is almost vertical, and projects into the costomediastinal sinus; that of the left lung presents, below, an angular notch, the cardiac notch, in which the pericardium is exposed.

Opposite this notch the anterior margin of the left lung is situated some little distance lateral to the line of reflection of the corresponding part of the pleura.