An 84-year-old man was discovered to have empty space where part of his brain should be. Experts say these “air pockets” are more common than you might think.

Next time you play Scrabble, try this on your opponent: pneumocephalus (10 extra points if you can pronounce it).

Pneumocephalus is the scientific name for the presence of air in the cranium.

You could see it if you used a CT scanner to examine a person’s right frontal lobe and found… nothing. Just empty space.

In fact, you may easily have had an air pocket without even knowing it.

And you might want to think twice before calling someone an airhead. You might intend it to be insulting, but you simply would be stating a fact.

The current interest in these brain parts that “aren’t there” stems from a case in Ireland.

According to a write-up in BMJ Case Reports, an 84-year-old man came to the emergency room with complaints that are fairly common among octogenarians.

He said he’d been feeling unsteady for several months, with repeated falls in recent weeks. In the three days leading up to his hospital visit, his left arm and leg had noticeably weakened.

“There was no confusion, facial weakness, visual or speech disturbance, and he was feeling otherwise well,” the case report stated.

The man appeared to be healthy, coping normally, and residing with his wife and two sons.

He didn’t smoke and he rarely drank. In fact, the doctors could find nothing in the man’s history or presentation that provided a reason for his distressing symptoms.

So they turned to the scanners. Both an MRI and a CT scan revealed a black hole where his right frontal lobe ought to be.

And it was sizable, too.

His pneumatocele, or pressurized air cavity, measured more than 3 inches at its longest — about the size of a softball.

Dr. Finlay Brown, who co-wrote the BMJ report, saw the patient when he came to the hospital. A general practice trainee from Coleraine, Northern Ireland, Brown was a member of the general medical admissions team at the time of the case report.

Brown, who isn’t a brain surgeon, told Healthline what he observed: “I did find in my research that up to 100 percent of patients will have some element of pneumocephalus following surgery, which usually resolved without issue.”

However, he also told the Washington Post, “In my research for writing the case report, I wasn’t able to find very many documented cases of a similar nature to this one.”

Dr. Nader Pouratian knows a lot about brains, with or without holes in them.

He’s chief of functional neurosurgery at the David Geffen School of Medicine at the University of California Los Angeles (UCLA).

“Normally, there are three main things in the head: the brain, blood, and spinal fluid,” Pouratian told Healthline. “During brain surgery, some spinal fluid rolls out.”

An air pocket will occupy what used to be brain space.

“There is a decreasement of blood and spinal fluid, and they are taking up space in the skull,” Pouratian explained.

He added that such a result is more likely following a head injury. The increased amount of blood takes up space.

As a result, “It pushes the frontal lobe back,” Pouratian said.

The skull is a closed system, he explained, but air does get in.

Through surgery is one way. Another is through small, damaged areas in the skull.

Between the nasal cavity and the brain, the bone is thin, he explained, making it easier for some fluid to run amok.

“The usual treatment is to get rid of the air and then seal the defect in the skull,” Pouratian said.

It’s something like a bicycle with a flat tire, only instead of pumping air into the tire, in the brain you pump it out. In both cases you end by patching the hole.

And the holes aren’t hard to find, according to Pouratian. Any scan would reveal it.

The symptoms might include personality changes or headaches, depending on what part of the brain is involved.

As for the Irish gentleman with the big hole in his head, he continues to thrive.

According to the BMI report, he first went through a period of observation and rehabilitation.

Following discussion with the neurosurgical team, he was offered surgery, which would have involved a frontal craniotomy and suture repair of the dural defect after evacuation of the pressurized air cavity, as well as excision of the osteoma performed by an ear, nose, and throat specialist.

“The patient made an informed decision not to proceed with surgery given risks and benefits” the report stated.

His inpatient stay was prolonged by a lower respiratory tract infection. The patient was taught about secondary stroke prevention and was advised to return in the event of worsening symptoms.

The left-sided weakness was noted to have resolved on follow-up 12 weeks later and the patient remained well.