I'm a junior Biology Student and I came across this Human Anatomy Question:

In respect to the bone characteristics, mark the correct answer:

A) Even bones: Palatine, Inferior jaw, Parietal.

B) Examples of Long Bones: Sternum and Radius-clavicle.

C) Some Mixed Bones are (I couldn't find a better translation for "ossos mistos" in portuguese): vertebrae, ribs, hip bones.

D)Plane Bones protect organs and form cavities, for instance we have: Ribs and Sternum.

E)Odd and Plane Bones: Occipital, Frontal and Sternum.

I am almost sure that options A through C are incorrect. I'm between options D and E, but in option E I am really sure only that the Sternum Bone is correct. I couldn't find a reliable source that said explicitly that the Occipital and Frontal Bone are Plane and Odd. And I think option D has a flaw mainly because the Sternum Bone does not form any cavities.

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    $\begingroup$ As you not in your question, I think there are some difficulties in translation. I suspect that "plane" should be translated as "flat", that "mixed" is likely "irregular", and "odd" and "even" are "paired" and "unpaired". Does that sound right? $\endgroup$
    – kmm
    Commented Jul 22, 2015 at 20:46
  • $\begingroup$ If you are voting down, please leave a comment. $\endgroup$
    – kmm
    Commented Jul 22, 2015 at 20:47
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    $\begingroup$ Why do you think the answer C is incorrect? %) $\endgroup$
    – Ilan
    Commented Jul 22, 2015 at 20:50
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    $\begingroup$ @kmm - here a new downvote. I am downvoting because this is a schoolbook example of a set of dry, contentless textbook-answerable questions not quite interesting for this community at large. I can't vote for closure as it is on topic. So, a downvote it is. $\endgroup$
    – AliceD
    Commented Jul 22, 2015 at 21:50
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    $\begingroup$ @AliceD I disagree. Here's a question with a valid attempt at answer, seeking clarification. Seems like a reasonable homework question. Maybe not the more interesting, but valid and worthy of answering. $\endgroup$
    – kmm
    Commented Jul 23, 2015 at 2:18

2 Answers 2


@KMM's comment above appears to be on the right rack.

"plane" = "flat"
"mixed" = "irregular"
"even" & "odd" = "paired" & "unpaired"

That being said:

  • A = FALSE because jaw bones are not paired
  • B = FALSE because sternum is not a long bone (it's a flat bone)
  • C = FALSE because ribs are not irregular bones (they're flat bones)
  • D = TRUE because both are flat bones and protect organs
  • E = FALSE but ONLY under the assumption of the persistence of a metopic suture (frontal suture) causing the frontal bone to be split (and therefore "paired").

If I had 90 seconds to answer this question I'd mark answer "C".

Vertebrae & Ribs & Hip bones all are mixed bones.


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