From the case:
Pneumothorax: deep sulcus sign
Frontal

Right deep sulcus sign in a child with a pneumothorax.
Case Discussion
These images are from Dr. Paula Brill's excellent pediatric radiology collection.
Dr. Brill is a professor in the department of radiology (pediatric section) at Weill Cornell.
This case was donated to Radiopaedia.org by Radswiki.net