I Got to See a Brain
Last night was anatomy lab for the neuroanatomy course I'm taking. I got to work with real brains and it was fascinating. Seeing one brain was worth a thousand pictures. Diagrams and drawings don't have perspective. You get no sense of size or spatial relationship. I worked with an average-size brain. It wasn't as large as my German shepherd's head.
The first thing that amazed was how small the middle cerebral arteries are. They're about toothpick width at their largest. Hard to believe something that small causes so much damage. The carotid arteries are about the thickness of a cotton swab. I was expecting something much larger. The remaining cerebral arteries weren't even smaller. Only the basilar artery came close in size to what I imagined, and it was just slightly bigger than a carotid artery. Seeing how small and fragile they are gave me a new perspective on brain injuries.
Another thing that surprised me was how large some of the structures really are. In books, pieces are shown in isolation to the rest of the brain, or enlarged so that everything is easily identifiable, thus distorting the size. The thalamus is pretty large and easily identifiable. The basal ganglia are huge. They seemed to take up most of the subcortical space. The caudate head alone is about the size of a dime. The internal capsule is almost two inches in length start to finish. The hippocampus is small and looks like a worm. It isn't the easiest thing to find but can't be missed once it is.
Brains are multicolored. Who knew? I thought brain tissue was either gray or white. It is. It's also shades of gray, very light brown, darker very light brown, etc. Each of the basal ganglia is identifiable by color as well as location. For the most part almost everything had a slight color difference for demarcation. Sure, I needed my glasses to see some of it but it was there.
My favorite brain part, the pons, was disappointing. How could something so important be so blah? It's huge in relationship to the brain stem. You can't miss it. I just expected more. None of the drawings I've seen of it did it justice. I wish one of the brains would have had the brain stem dissected. I would have liked to see how the interior fibers ran. Given all the pons does, it was under-represented.
The spinal cord is the size of a medium pen and gradually gets smaller. Nerve roots are tiny but visible. I have a new appreciation for surgeons who work around them. No wonder spinal surgeries take so long. The largest one I saw was the size of a number 2 pencil lead. I'll take the rather large and cumbersome pons or basal ganglia any day.