Is there any simple explanation as to why human bones are more curved than straight and are thicker at ends and thinner in the middle?

  • $\begingroup$ Can you explain what you mean by curved? Do you mean the surfaces of the bone are curved because of the greater width of the ends, or do you think the actual bone (i.e. the actual axis of the bone) is curved (one is true, the other may be an illusion, or present in disease.) $\endgroup$ Aug 14, 2019 at 16:28
  • $\begingroup$ @anongoodnurse - I meant the axis. $\endgroup$
    – brilliant
    Aug 14, 2019 at 16:31
  • $\begingroup$ Thanks. The anatomical axis of normal long bones is usually a straight line, but the outsides can be curved. Just clearing up terminology. Ribs are obviously curved, and quite commonly fractured as a result. This might be rightly deleted as an answer in a comment. $\endgroup$ Aug 14, 2019 at 16:57

1 Answer 1


The slight curve allows bone to absorb shocks better.

This curve allows the bone to act like a spring and flex a little bit. One issue as bone get older is that they become harder and, therefore, more brittle which leads to the elderly breaking bones for a fall that younger individuals just get a bruise. Young children often get stick or "splitting" breaks where the bone does not break but separates as the bone is still soft.

The ends tend to be thicker as that is where the joints are and there are forces that need to be absorbed.

Of course, if the load applied to the bone is just too much or it is a sharp shock then bones will break, but really the skeleton is nature's design for a suspension system to allow us to do what we need to do walk, run, stand, etc

This set of slides makes good reading, with things like "less ductile", "elastic behaviour" and "strength in compression" worth looking for:

Mechanics of bones by Phillipe GILLET

A quick search gave many results but of these two shown the first seems very interesting from an engineer's perspective:

  1. shock absorbing "goo"

  2. shock absorbtion

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    $\begingroup$ While I think you're right, you can improve your answer by adding literature that supports your thoughts. $\endgroup$
    – Arsak
    Aug 9, 2019 at 7:54
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    $\begingroup$ I wasn't thinking about calculations or similar sophisticated level, rather about an introduction to biophysics for example that covers what you've written. And sorry if my comment reads like an attack, that wasn't my intention. I just know that the community prefers well referenced answers to maintain quality of the site. $\endgroup$
    – Arsak
    Aug 9, 2019 at 16:40
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    $\begingroup$ While this sounds plausible, it is not correct. Long bones are not curved and they are not springs of any type. Furthermore, your sources do not support your assertions. $\endgroup$ Aug 14, 2019 at 15:50
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    $\begingroup$ The two sources given are unrelated to the question asked and the answer given. Please provide appropriate references related to the specific question and answer asked, not unrelated trivia. I worry that the presence of unrelated citations appears to give an answer more credibility than it deserves - I find this worse than lack of citation and perceive it as a form of academic dishonesty. $\endgroup$
    – Bryan Krause
    Aug 14, 2019 at 15:58
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    $\begingroup$ Solar Mike, it is not the responsibility of the commenter to prove you wrong; it is the responsibility of the answerer to prove their answer is correct. Users are encouraged to point out wrong answers, not to argue with them. $\endgroup$ Aug 14, 2019 at 16:13

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