In a recent episode of our podcast with anatomist and forensic anthropologist Prof Sue Black, we discussed what it’s like to dissect a human body, how a single bone can tell a whole story, and what makes the skeleton so important.
We’ve dug out the best bits of the conversation to share with you, but be warned – some of them might send shivers down your spine.
Our bones bleed (and are very much alive)
“Bones contain a huge number of minerals, a huge amount of calcium, a good bit of phosphorous and other trace materials as well. And that becomes really important, because bones as you grow them and as they mature, are always regenerating themselves.
“So, the bones that you have now have probably regenerated within the last 10, 15 years almost in their entirety. It’s a living tissue.
“We think about bones as being dead dry things. But when you’re alive, they’re alive, too. If you cut them, they bleed. If you break them, they hurt.
“They have a massive blood supply. Arteries go into bone and veins come away. Deep, oxygenated blood in the arteries is going into the tissues that form the bones – because it’s live tissue, so it needs to have oxygen – and as it’s producing by-products, it needs to have them taken away.
“It’s a very, very busy factory, the human skeleton.”
You are what you eat
“Bones need to constantly replenish and replace themselves, just like your skin does. But they do it at a fairly slow rate. What that means is that every time you replace something in your skeleton, it is a reflection of the building blocks that you have eaten to create that material. You are literally what you eat. Your bones can only be made off the things that you ingest.
“There’s some very clever work, which is not my field at all, called stable isotope analysis. That analysis, which looks at the proportions of things like nitrogen and oxygen in a sample, can tell you where that individual was living whilst those building blocks of bone were being put together.
“So, for example, looking at the bones of an arm that were washed ashore quite a few years ago, Prof Wolfram Meier-Augenstein, who does stable isotope analysis, was able to say it was likely that the individual had been living in Scandinavian countries – just simply because the stable isotope signature leads you to believe that’s the most likely place in the world. It’s incredibly clever, but very, very logical when you understand how bone is formed and how it continues to mature over time.”
Forensic TV shows led to a surge of (misplaced) interest in the career
“We did see, in the 1990s and the 2000s, a real explosion of forensic as being something in the media that took everybody’s imagination, whether it was television or films or novels. It really took off. And you can understand that because, I think, the human is a curious primate and being able to have a mystery that you can solve… We all love a bit of that.
“What then happened was a lot of young people, who had never thought about forensic as a career for themselves, were brought to it by the unrealistic nature of much of this material. Universities being universities of the time were not necessarily going to be overly moralistic about this or ethical. If there were a lot of students wanting to do something with the word forensic in it, then they put on courses with the word forensic in it.
“Back in about 2010 I did a trawl on UCAS to look at the number of courses that had the word forensic in them… I think there were about 468 undergraduate courses. But it was things like ‘Forensic Investigation and Modern Dance’ or ‘Forensic Investigation and Early Christian Doctrine’. That’s universities just being silly.
“I think that typified what happened to forensic at that time. It’s moved on since then, quite significantly because, of course, very quickly those young people realised they were not going to get a job in the forensic field by having a degree in ‘Forensic Investigation and Modern Dance’.”
Human ribs should extend all the way to our abdomen
“The human skeleton is critical for protection. Think about where you have really soft areas of the body. The brain is a very, very soft tissue, the heart and the lungs are very soft tissues. We need to protect them in a little bony shell.
“Of course, we should really be protecting our abdomen as well. But if you think about it, we started off as a quadrupedal animal. So actually, the front of our body was underneath us. It was originally better protected than it is now.
“We are a product of what that change of evolution has been.”
Machine learning is helping solve crimes
“Tech has helped when it comes to the other side of work that I do, which is identification of individuals from images. These images are usually of child sexual abuse, and the part of the perpetrator that is in that image is often the back of their hand.
“We’ve been doing a lot of research, on an anatomical perspective, on how to identify perpetrators from the anatomy of their back of their hands. The features that you can see on the back of your hands, anatomically are really valuable. So, the pattern of superficial veins on the back of your right hand will be different to your left. They’ll be different if you’re an identical twin.
“If you look at the pattern of skin creases across the knuckles of your fingers, they’re different on each one and different across both of your hands. If you have freckles or birthmarks or moles, they’re in a different place to anybody else. If you have scars, chances are they’ll be a different size, different orientation, different location. So, there’s all sorts of pieces of anatomy wrapped up in the back of your hand.
“We’ve been working on this for about 16 years now and we’ve helped the police to secure about 30 life sentences and about 400 years of prison sentencing.
“The next stage of development is in relation to AI and machine learning. So, when the police download images from somebody’s phone or computer, they may have hundreds of thousands of images. Often 10,000 or 20,000 at a time. It’s not possible for us to go through 20,000.
“But if we can train a computer to find a hand in this image, and if you can find a hand, what’s the vein pattern in this image? What’s the knuckle crease pattern in this image? You then have a pattern for that individual. You create an algorithm that will allow you to do that. You can then run that algorithm through the database of hundreds, thousands and sometimes even millions of images and say, does this person appear in any other images? And if they do, then what you can start to do, hopefully, is connect cases that you weren’t able to connect before.
“Perpetrators move around the world. So, you get the French police picking up images in France, you’ll get the American police picking up images in America because it’s on somebody’s computer. We now might be able to say, yes, that’s the same individual.
“So that’s what AI and machine learning, we hope, will be able to do for that part of the research that I carry out.”
Prof Sue Black could teach for eternity
“Right at the end of my new book, Written In Bone, I decided that I would write a list of all of the things – starting at the top of my head to my toes – of all the things that I know my body has gone through over this half century and more, and how that would manifest on the skeleton.
“So, say somebody found my bones. They’d be able to identify that healed fracture of my left collarbone. They’d be able to point to the arthritis in my big toe. All of those sorts of things I’ve listed. It’s a really interesting exercise to do, thinking about your own body and all the things that you’ve gone through. Have they left a mark?
“I also leave that list – which I’ll add to, because hopefully I’ve got a few years left in me yet, and there’s a lot more that I can abuse my skeleton with – when I die. I think I would be a hypocrite as an anatomist if I didn’t leave my body for dissection. I want it to be the anatomy department at Dundee University, because that was the department that I had 15 years of work in. But also, because there we developed a method of embalming, called ‘Thiel’, which is a soft fix embalming. That means the bodies are very, very lifelike. So, I’d like to be thieled.
“I’d like to be dissected. I’d rather be dissected by science students than either medics or dentists, and my reason for that is the medics and dentists just don’t have the time in their curriculum to do the depth of dissection that a scientist does. I want to be thoroughly pulled apart, tissue by tissue, so that students can learn the maximum that they can from this body. I’m happy for them to collect together all the sort of viscera and the muscle and skin and everything else and cremate that. There’ll be nothing left. But I’d like them to take my bones.
“Then, ideally, I’d like to be strung as an articulated skeleton in the dissecting room. Because you then have the opportunity to teach for the entirety of your death, which is the most appropriate thing, as a teacher, isn’t it? I’m an anatomist and a forensic anthropologist who wants to be an articulated skeleton when she grows up, which feels just right.
“And if I’ve got the list alongside it, of all the things that have happened to me, then whoever is looking at my body and my bones can go, ‘Yeah, there is that and there is that. And oh, she missed that, she didn’t put that in the list.’ That, to me, would just be fantastic. But whether it will happen, you know, what you want and what you get is not always the same thing.”
Listen to more episodes of the Science Focus Podcast:
- Brian Switek: How did bones evolve?
- Mark O’Connell: Transhumanism: using technology to live forever
- Bill Bryson: What should we know about how our bodies work?
- Nathan Lents: Everything that’s wrong with the human body
- Ritu Raman: Can you build with biology?
- Aleks Krotoski: What happens to your data when you die?