The Skeletons in the Closet
How do we determine the sex of a skeleton?
Here are some ways:- Female bones are smaller. (Generally)
- Ilium more expanded. (See diagram)
- Sacrum flatter and broader. (See diagram)
- Pubic arch is rounder in the female than male. (See diagram)
How do we determine the age of a skeleton?
Here are some ways:- By the number of erupted teeth.
- By the cartilages of the ribs which ossify as we age.
- Ramus' angle with body - obtuse (before teeth) right angle (with) obtuse (after teeth in old age) (see diagram below)
- Condition of the epiphyses (rounded end of long bone) with regards to their attachment to their respective shafts.
How to Use Human Bones to Determine Stature
- A way to measure the length of the femur (the thigh bone) in centimeters. If you are doing an informal analysis, you can use a tape measure, but professional forensic scientists usually use a device called an osteometric board to measure bones.
- Multiply the length of the femur in centimeters by 2.6. Add 65 to the result to obtain the approximate height in centimeters of the person whose bones you are examining.
- Measure the length of the humerus (the bone that goes from the elbow to the shoulder) in inches.
- Multiply the length of the humerus in inches by 2.8 if the bones are thought to be from a female. Add 28.1 to the result to find the approximate height in inches.
- Multiply the length of the humerus in inches by 2.9 if the subject is thought to be male. Add 27.8 to the result to find the approximate height in inches.
- Measure the length of the tibia (the larger bone in the lower leg that runs from the knee to the ankle) in centimeters.
- Multiply the length of the tibia by 2.42 and add 81.93 to the result to get the approximate height in centimeters of a Caucasian male. For a Caucasian female, multiply the length of the tibia by 2.90 and add 61.53 to the result to obtain the approximate height in centimeters.
- Multiply the length of the tibia by 2.19 and add 85.36 to obtain the approximate height of a black male in centimeters. For black females, multiply the length of the tibia by 2.45 and add 72.56 to the result.
- Multiply the length of the tibia by 2.39 and add 81.45 to obtain the approximate height of a Chinese, Japanese, Eskimo, Native American, Siberian, Malayan or Mongolian male. The exact number to add to the length of the tibia to obtain the height of a female of one of these races or nationalities is not known, but females are generally 10 to 20 cm shorter than males.
- Measure the femur and the fibula (smaller lower leg bone that runs from the knee to the ankle) in centimeters.
- Add the two measurements together and multiply the result by 1.31. Add 63.05 to the result to obtain the approximate height of the subject in centimeters.
I'm suppose to disclose 7 things about myself:
1) I'm a writer.
2) I love Tim Horton's coffee.
3) I'm really too lazy to follow award rules.
4) See above.
5) See above.
6) See above.
7) See above.
I'm also suppose to give it to ten people. But, because that would take a lot of time away from editing my novel (and because my publisher is probably reading this blog post) I'll give it to one blogger. I'll give it to a blog run by my publisher! How's that!?
Sources: Aids to Forensic Medicine and Toxicology
Wikipedia: Coccyx, Pubic Arch, Epiphysis
Features of the Human Body
How to Use Human Bones to Determine Stature | eHow.com
There are too many other things we use when looking at a skeleton to do these things to mention alternatives, but I did want to comment on a few things.
ReplyDeleteOne general comment is that none of these individual tests are make-or-break. Every one points to a range of possibilities or to a probability, and most of the time there are some minor conflicts amongst them. Most skeletons we see in the lab, for instance, have some male characteristics and some female characteristics. The lab analysts can see age ranges that span twenty years sometimes. It's important for authors (and consumers of news) to understand this because it is rarely appropriate for someone, no matter how expert, to look at one bone and make a quick and certain determination about these things.
Female bones are smaller. (Generally)
While true as a guidelines and sometimes useful in a mass gave type of situation, or as one component of a statistical analysis, it is very unusual for a forensic anthropologist to look at the bones of someone and say, "Those are small, it's probably female." (And there are exceptional cases in which it can, but that get complicated.)
Note: Before puberty, the sex cannot be determined from an examination of the bones.
This is typically true, but since we have a skeleton with no soft tissue, we don't know if it's hit puberty or not. It's usually better to say that the sex cannot be accurately determined from bones, prior to the development of secondary sex characteristics.
Ramus' angle with body - obtuse (before teeth) right angle (with) obtuse (after teeth in old age) (see diagram below)
This one can be helpful for getting you to a period of life, and it tends to make you think, "old person," but can also just mean, "tooth loss."
Note: To determine stature, the whole skeleton should be laid out and measured. 1.5 - 2 inches should be allowed for the soft parts.
This is almost never done and is highly suspect as there is incredible variation amongst the parts. There are formulas, based on sex and race, that forensic anthropologists use to make estimates of stature based on long bone length. While I'm sure it's done, I've personally never heard of anyone in a lab or scientific context using this formula you describe.
four out of four, I guess I know my skeletons, not that I have any in my closet ...
ReplyDeleteThank you, Nevets. I agree totally! I did not mention everything because... well, it would take pages. I just wanted some simple things. And of course, not everything will always be the same for each individual case.
ReplyDeleteHowever, this blog is intended for writers (not doctors - I hope...) so for the little tidbits. If you are a doctor, please go to medical school.
Thanks for the comment, Nevets! I have added a better reference just for you.
Also, to my other readers, these blogs are intended mainly for me (I keep my research handy on this one website so I know where to come when looking up information) and so it does not replace research of your own. Nevets is right, not every situation is the same. Sometimes the situation has never been investigated in real life (probably has, but not been documented) and so you might have to take some creative license.
Have a great day everyone!
CD
Congrats on the award and not following the rules is the only way to go. ;)
ReplyDelete@Clarissa - Yeah, I mean, I have multiple thick books on my shelf right now to cover this stuff. So you can't blog it all. haha
ReplyDeleteMy main point was, I suppose, to caution writers against overplaying certainty from small bits of information. There's a certain TV show I won't name that, while highly entertaining, and sometimes on the mark, has helped give too many writers the impression that you can glance at one bone and know everything with confidence. :)
Fascinating stuff! And I got all four correct. See? Hours and hours of TV shows like CSI have paid off!
ReplyDeletehi miss clarissa! one of my most best school subjects is science so for sure i love this post. more blearning! :) i got a story thats got a skeleton in it and now im thinking im gonna use that tooth info for getting the age of it.
ReplyDelete...hugs from lenny
Clarissa - Thanks for this. Every single time I visit your blog, I learn something useful. It's so important to me, too, that authors make the effort to be accurate that I'm glad you're there to help us do that. Thanks :-). But please - no more math!! ;-)
ReplyDeleteGreat quiz and a very interesting post. From watching Bones, I actually knew the answers. :) I have to say, you have a way of making science much more interesting than it was when I was in school.
ReplyDeleteMason
Thoughts in Progress
I love that quiz and thanks for the interesting info about skeletons. You're a one-stop, murder-mystery shoppe! lol :) Congrats on the award.
ReplyDeleteNow to figure out a way to add some skeletons to my story...
I find this fascinating, being a pre-med drop out and all. :) Although, I love watching and reading forensic science I probably will never write a crime style book.
ReplyDeleteGreat Post!
very cool. And I knew that part about the pelvis and sex/gender... Love these posts~ :o)
ReplyDeleteCongratulations of the award. You took that skeleton right out of my closet. LOL
ReplyDeleteNancy
N. R. Williams, fantasy author
I got the first two wrong--oops. And I thought I was learning so much from those archaeology TV programs . . .
ReplyDeleteCongratulations on the award!
Er... all I saw were maths and numbers. And skeletons. Lots of them. And I got the last question right and the first two but the last question was the most important! LOL!
ReplyDeleteAnyway - the human skeleton is totally fascinating - I was going to read Archaeology as my second degree and so am totally intrigued by what a skeleton may reveal about it's owner!!
Thanks so much Clarissa!!
Take care
x
I got three out of four and if I were in school i would demand a recount
ReplyDeleteover the holidays I saw one of the poisonous plants you talked about and yelled - lets just say passers by mistook me for a nutter.
Great post. Science is cool.
ReplyDeleteYay, I scored 4/4!
ReplyDeleteI'm not a biology fan but I don't enjoy learning how to tell things from bones. That probably comes from my early and morbid fascination with archeaology and history documentaries.
Great post and congrats on your award!
Jai
This post was so fun. Congrats on the award and breaking the rules. Life is much more fun when we break the rules.
ReplyDeleteVery useful post. I have bookmarked it as it may come in handy for my Danish WIP.
ReplyDeleteCool stuff here :)
ReplyDeleteI scored a 10/10 for noticing peoople but I seldom notice what they're wearing. And in my writing I never think of describing what someone is wearing. When I read a book I skip over descriptions of clothing. So maybe you're write about how it affects our writing.
ReplyDeleteI'm rather like you. I have to add those in later during one of the edit passes.
ReplyDeleteI'm also not terribly good at remember whether I've met people. And I'm horrible at remembering names.
Hi Clarissa ... I know where to come when I find a body somewhere .. I can then ring the police and give them some clues .. nope I'd be running in the other direction .. fascinating information - fortunately I got 4/4 .. even though I haven't watched "Bones" .. I hope I sleep tight tonight?! Enjoy the weekend .. Hilary
ReplyDelete