Deep sulcus sign

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

In radiology, the deep sulcus sign on an x-ray in an indication of a pneumothorax.^{[1] [2]} In a supine film (common in the ICU), it may be the only indication of a pneumothorax because air collects in the anterior costophrenic sulcus instead of the apex (of the lung) as with an upright film.