A CT scan revealed a bit of a surprise in an 84-year-old patient's head. The scan was at a doctor's request after months of the patient feeling unsteady, falling often, and losing feeling in his left arm and leg.

With the symptoms pertaining to just the man's left side, doctors suspected a stroke, but the scan revealed a 9 cm pocket of air in the right frontal lobe of his brain.

An MRI confirmed the presence of this pneumatocele (pocket of air), which probably compressed the blood vessels to the point that it cut off blood circulation to part of his brain. This likely caused a small stroke that then led to his left-sided weakness.

Doctors offered surgery to remove this pocket of air. At the risk of having more strokes, the man decided that at his age the risks of sucking the air out of his head could also suck and decided not to move "a head."

How did air get in there? Surgery, a bad infection, a tumor, an injury, or even bad bouts of sneezing or coughing can create a hole in the skull that allows air to seep in and expand.