Daily Archives: February 4, 2011

The Circle of Willis

Bottom View of Brain (not its best angle, frankly)

“Thomas?”  The nurse stood in the doorway of the doctor’s waiting room and indicated that my turn had finally come.  I put down the issue of National Geographic I’d been browsing — one of the first that was published in color, I believe — and attempted to follow the nurse.  That proved to be difficult; since I had been sitting in the same position for such a long time, my foot was asleep.

She led me to an examining room, took my blood pressure and pulse, jotted a few notes on my chart and then swept out of the room with a frosty, “The doctor will be right with you.”  Of course, she meant “right with you” in the same ironic sense that others in the medical profession say, “This might hurt a little.”

There were no magazines in the examining room; for a while I bided my time by feeling my whiskers grow.  At one point I found myself hoping that the doctor would want a urine specimen, because I was sure I could comply.  To take my mind off that discomfort, I looked at the decorations in the room, which consisted of extruded plastic illustrations of the human anatomy, rendered in great detail.  That’s when I made the discovery that I — we — have a body part that until that  moment, I didn’t know existed.

It’s called the Circle of Willis.  Be honest — you didn’t know you had one, right?

We’re accustomed to organs and appendages with names that are Latin or Greek.  You’ve got your scapula, your larynx, your pancreas and so on.  But the Circle of Willis — what the heck is that?

The first thing I thought of was an old television show called Diff’rent Strokes, which was memorable because at least once per episode, child actor Gary Coleman would utter his signature line, “What you talkin’ ’bout, Willis?”  For a moment I imagined the Circle of Willis being that character’s council of advisors and confidants.

Nope.  It turns out that the Circle of Willis is part of the brain, and a very important part at that.  It’s a circular connection of arteries on the bottom side of the brain; all the main arteries that supply blood to the hemispheres of our brain branch off from the Circle of Willis.  Because of that design, if one of the main arteries becomes occluded (blocked), other smaller arteries in the loop can sometimes come to the rescue, possibly averting a stroke.  In other words, there is some redundancy built into the Circle of Willis to maintain maximum brain efficiency.  That’s what Willis is talkin’ ’bout.

So who was Willis?  Thomas Willis was a 17th century English physician who did a lot of research on the brain and nervous system.  Some of his dissections were performed on the victims of public executions, and in one instance, a recently hanged woman named Anne Green began to stir and came back to life, just as Willis was beginning his dissection.  Surprise!

After the miraculous recovery of Anne Green in 1651, his services were in great demand.  There is no record of how long Thomas Willis kept his patients waiting.