So I have a humanoidish race of creatures that don't have clavicles and gives them more mobility of their arms/ hyper mobility. While ik about the Cleidocranial dysostosis, the birth defect or mutation that means the person is born with partially formed or no collar bones as well as other bone development issues like with the cranium and also with teeth.

However, that occurs in creatures that are designed on average to have collar bones, what about a race that just naturally didn't have them?

What would that affect? Would it make any sort of sense in a body that fairly resembles the human skeletal structure? If not what would without having to change their bipedal stance?

  • 3
    $\begingroup$ Clavicles are a primitive feature. Bears do not have clavicles but can walk on two feet just fine. Primates have retained their clavicles because our arms need (1) a wide range of motion and (2) need to be able to transmit force along a very wide angle -- we primates are able to locomote by brachiation, which is sort-of our signature mode of locomotion. $\endgroup$
    – AlexP
    Sep 29 '19 at 6:39
  • $\begingroup$ If you break either of your collarbones, you lose the use of the arm on that side. Side note its a game-changer in a fight. $\endgroup$ Oct 7 '19 at 3:05

Based on http://anthropologicalconcepts.weebly.com/fun-fact-fridays/the-clavicle

It would seem the collarbone is essential for the ability to climb trees, essentially the ability to pull with our arms. The collarbone is also a major player holding our shoulders in place, and the balancing our shoulds, arms and upper body when we walk/run.

Dogs among many other species do not have collarbones, though they do have a simpler cartilage version that helps anchor muscles and sinews. This allows the dog a greater speed and flexibility, that they need when hunting down prey.

Cats and bears do have a collarbone, but its "free floating" in the sense it's not attached to the rest of the skeleton like the human one is. I assume that puts them somewhere in between, with the power to climb (pull with their "arms"), and still race down prey, but not as effectively as humans and dogs are in their respective fields.

So a human like creature with no collarbone, I would say would have a hunched over really bad posture times 10 look. Walking would be less smooth, with more upper body motion. Greater flexibility but less pulling power, to the point where they might not even be able to pull them self out of a hole.

Finally FYI, I have no medical education, so it's pure guesswork based on what I could find on the subject online :)


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