Pneumothorax-Deep-SulcusCase: A 18-year-old male with no medical history presents to the emergency department (ED) complaining of “feeling like I am having a heart attack” which started suddenly 1 hour ago. The patient ate from a food truck the night before and developed several episodes of forceful vomiting prior to arrival in the ED. What finding in this supine chest radiograph aids in the diagnosis? Click on image for a larger view.

Poll Results

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Deep Sulcus Sign


The deep sulcus sign was first described by Gordon in 1980 as a deep lateral costophrenic angle on the involved side.1 In this example, it is on the patient’s left side (arrow). It is an important radiograph finding to be aware of in making the diagnosis of pneumothorax, because it may often be the only abnormal finding.2 The cause of the sign is air tracking anteriorly and caudally along the pleural space and can be found on supine films. Which makes this finding particularly important for SUPINE critically ill patients. Air appears as a hyperlucency on radiographs which leads to the appearance of a deep lateral costophrenic angle on the side with the pneumothorax.


Wrong Answers

Wrong AnswerDescriptionAssociations
Air Fluid Level3Intrapulmonary cavitary with line that separates air from fluidCavitary lesions, lung abscess, tuberculosis
Kerley B Lines4Short horizontal lines, usually found in the lower zone peripheryCongestive heart failure, interstitial lung disease, pulmonary edema
Widened mediastinum5Mediastinum measuring a width >6 cm on upright PA chest xray, or >8 cm on supine AP chest xrayAortic aneurysm / dissection, anthrax inhalation, esophageal rupture, mediastinal mass

Gordon R. The deep sulcus sign. Radiology. 1980;136(1):25-27. [PubMed]
Smally A, Suozzi J. Images in emergency medicine. Deep sulcus sign. Ann Emerg Med. 2007;49(5):717, 725. [PubMed]
Bhardwaj B, Bhardwaj H. Air-fluid level in the right lung. Lung India. 2014;31(2):179-181. [PubMed]
Koga T, Fujimoto K. Images in clinical medicine. Kerley’s A, B, and C lines. N Engl J Med. 2009;360(15):1539. [PubMed]
Lai V, Tsang W, Chan W, Yeung T. Diagnostic accuracy of mediastinal width measurement on posteroanterior and anteroposterior chest radiographs in the depiction of acute nontraumatic thoracic aortic dissection. Emerg Radiol. 2012;19(4):309-315. [PubMed]
Nikita Joshi, MD

Nikita Joshi, MD

ALiEM Chief People Officer and Associate Editor
Clinical Instructor
Department of Emergency Medicine
Stanford University
Nikita Joshi, MD


Emergency Medicine Doctor Associate Editor of ALiEM Gun Sense Advocate #FOAMed #Docs4GunSense #MomsDemandAction Tweets represent my own views and opinions