The supine chest x-ray shows deep sulcus sign.

The chest x- ray is understandably technically inadequate. The patient has been intubated and there is a right sided subclavian central line.

Deep sulcus sign on the right side which is on the same side as the central line is due to complication related to central venous access. In a supine patient, air outlines the costophrenic angle, extending towards the hypochondrium. This sign is useful in the diagnosis of a pneumothorax especially when the lung fields are obscured by defibrillation pads in a sick patient.