I have been writing this blog for nearly six years, and my curiosity and pleasure in reviewing interesting, unusual radiographs are widely known among my colleagues. On a recent shift, a friend brightened on seeing me and exclaimed, "I want you to take a look at this!" She immediately opened PACS to this image.
"What's the story?"
"An elderly lady had a mechanical fall at home, coming down on her right shoulder."
"What do you think?" I asked, glancing at my med student.
"The joint looks too close. There is a lot of DJD. I can't tell if there is a fracture."
"Yes, but look at the whole image, not just the joint. Look for something that isn't supposed to be there," I said.
He pointed at the irregular blackened area. "This here, it is black. Is it air? Why's that there?"
That is the question: Why is air there? It would seem most likely from an injury to the lung, although air can track down the neck from facial and upper airway injuries. It is also possible for air to track upward from a pneumoperitoneum. The thorax would seem to be the most likely culprit in this case, however, with the air seemingly centered around the body of the scapula.
"And the noncontrast CT showing a pneumothorax is next up?" I asked my colleague.
Air was clearly dissecting its way along the chest wall muscles, traveling anteriorly under the scapula and down the body. The perpetrator of this abnormality almost certainly was the minimally displaced rib fracture (arrow), puncturing the lung underneath. The air seemed to bubble up initially from there. Surprisingly, radiology did not call a pneumothorax. It was only a faint sliver if it was there.
How did the air get there if there were no pneumothorax?
It was thought that this elderly woman's lung had scarring, so when the rib pierced the lung, the fibrosed pulmonary tissue stayed adherent to the thoracic wall. The air had to go somewhere, so it went freely into the chest wall instead of accumulating in the pleural space.
As with most cases, the air resorbed over the next week or so without further incident.
Tip to Remember: Look at the whole radiograph, not just the area of initial clinical concern. Tunnel vision can miss significant abnormalities. After looking at the area of clinical concern, view the entire image, or a significant finding can be overlooked.