S sign of Golden

What is the S sign of Golden?

With upper lobe atelectasis, the major fissure is pulled superomedially and appears as a straight or concave line on a frontal chest radiograph. However, when the atelectasis is secondary to a central obstructing mass, the central portion of the major fissure will appear convex due to the mass, whereas the peripheral fissure will appear concave as the peripheral lung atelectasis. Thus, on a frontal chest radiograph, the fissure will have an S shape (on the left) or a reverse S shape (on the right). This “S sign of Golden” (first described by Golden in 1925) therefore signifies presence of a central obstructing mass with associated resorptive upper lobe atelectasis.