You were born with more bones than you have now

[tangent]

Or so clames a blerb on PBS. First I've heard of this. What bone or bones do you loose in the early years of your life?

-t

[DrBaboon]

Bones are not lost, so much as consolidated. It seems like kind of a trick question type of approach.

However, the number of bones in a complete human skeleton varies -- IF you are counting the various possible types of sesamoid bones (FWIW - the largest of which are the patellas, though we don't usually think of them in that fashion).

Thumbs, little fingers, big toes and little toes may or may not have sesamoid bones of various sizes. If they are big enough to be an obvious sesamoid bone, it's just an interesting finding on x-ray. If they are small, we sometimes wonder if they might represent a small fragment from a fracture (if it's not apparent the larger bone nearby in the finger or toe is truly intact).

Another trick question applicable here, would be the possibility of developing pseudoarticulations after sub-optimal fracture healing - it converts a bone into more than one bone, if you want to think of it that way.



Now if you want to have some gross anatomy fun, and/or embryology fun, some muscles may or may not develop in a given individual.

My medical school cadaver had a sternalis muscle on one side, but not the other, and IIRC, she did not have palmaris muscles, whereas some of the the cadavers my classmates dissected had palmaris muscles, but no sternalis muscles.

It's of little to no clinical consequence - I'm sure that each of the people who donated their bodies never knew or missed these particular muscles.

[DrBaboon]

You know, this is one of those aggravating things that could become a peeve for me. Since I'm posting again as I sit here and stew, maybe it's already a peeve. Beats me.

I have encountered situations where a first aid course or some other kind of training wanted people to give an exact number for how many bones there are in the human skeleton.

Obviously, it's convenient to teach and test whether people can regurgitate that number. But is the number valid as a "universal constant?" Obviously not. Nonetheless, it's a mostly constant number for otherwise "normal" and/or healthy individuals - whatever that means.

You also run into problems with who ever writes a test question like "how many bones in a human," and what their fund of knowledge is, as well as whatever their frame of mind was when they counted the bones (or if they simply relied on someone else counting for them).

For example - do you count the ossicles in the ears as bones? They're not exactly part of the axial/weight bearing skeleton, but they are bones. They are also susceptible to various arthritises and metabolic bone/joint diseases. The various cartilages that articulate and move in the larynx are not bones, but they can be affected by arthritises and so on. I mention that to point out the joint issue.

I've also had more than one patient who thinks they have cancer when they finally discover their hyoid bone.

Then there's the whole question of transitional vertebrae. IOW - "six lumbar segments seen on x-ray." Is it an incompletely fused S1 that looks like it's now L6, or is it a lumbarized T12 or whatever? And do you have the visual range covered on the lumbar spine films to see the context. That is, since you're not counting thoracic vertebrae on a lumbar film, how can you count 12 thoracic vertebrae? You get the idea, possibly.

This is one of the irritating test questions that the more you know, the more you are likely to give an answer that differs from what the teacher was looking to get.

[tangent]

your right - trick question. I do remember learning about skelital bones growing together.

thanks,

-t