One quarter of the blood goes to the brain

Two of the theatre nurses, bent over with the effort, slowly push the heavy microscope up to the table and I climb into the operating chair behind it - a specially adjustable chair with arm rests. This moment still fills me with awe. I have not yet lost the naive enthusiasm with which I watched my first aneurysm operation thirty years ago…The view down the microscope into the patient’s brain is indeed a little magical — clearer, sharper, and more brilliant than the world outside, the world of dull hospital corridors and committees and management and paperwork and protocols. There is an extraordinary sense of depth and clarity produced by the microscope’s hugely expensive optics… 

I choose one of the retractors — a thin strip of flexible steel with a rounded end like an ice-cream stick and place it under the frontal lobe of the woman’s brain. I start to pull the brain upwards from the floor of the skull — elevation is the proper surgical word — cautious millimetre by cautious millimetre, creating a narrow space beneath the brain along which I can now crawl towards the aneurysm. After so many years of operating with the microscope it has become an extension of my own body. When I use it it feels as though I am actually climbing down the microscope into the patient’s head, and the tips of my microscopic instruments feel like the tips of my own fingers. 

I point out the carotid artery to Jeff and ask Irwin for the microscopic scissors. I carefully cut the gossamer veil of the arachnoid around the great artery that keeps half the brain alive. The arachnoid, a fine layer of the meninges, is named after the Greek word for spider, as it looks as though it was made from the strands of the finest spider’s web… 

Armed now with retractors I start to prise apart the frontal and temporal lobes, held together by the arachnoid. Cerebral-spinal fluid…as clear as liquid crystal, circulating through the strands of the arachnoid, flashes and glistens like silver in the microscope’s light. Through it I can see the smooth yellow surface of the brain itself, etched with minute red blood vessels — arteriols — which form beautiful branches like a river’s tributaries seen from space. Glistening, dark purple veins run between the two lobes leading down toward the middle cerebral artery and, ultimately, to where I will find the aneurysm.

— from Do No Harm by Henry Marsh (2014)

Image: Surgeon Conducting a Trephination in Guy of Pavia’s Anatomia. Unknown artist circa 1345. Musée Condé, Château de Chantilly, Chantilly (Ms. 334) via wtfarthistory