I Medical Physics: the spine as a pivot

[Mahavir]

Hi everyone,
So, as I came across a point that I'm struggling to grasp and I was hoping someone here could kindly help me out.

I've attached a diagram that describes the issue.

• T represents all the muscles acting on the spine;
• R is the force of the spine (pivot).

Where I get confused is why a larger force T is necessary to balance the forces?

Thank you in advance.

Kind regards,

Mahavir

 

[A.T.]

Where I get confused is why a larger force T is necessary to balance the forces?

How do the lever arms of "the forces" compare to the lever arm of T?

 

[Mahavir]

How do the lever arms of "the forces" compare to the lever arm of T?

Hi A.T.,

Thank you for your reply. Oh, thank you. The lever arm of the Force T (spine) is a lot shorter than the lever arm of W and therefore in order for their torques to balance, the force exerted by T needs to be a lot higher than the weight.

Is that correct?

 

[Mahavir]

How do the lever arms of "the forces" compare to the lever arm of T?

I would really appreciate your answer to my above query, please.

 

[A.T.]

The lever arm of the Force T (spine) is a lot shorter than the lever arm of W and therefore in order for their torques to balance, the force exerted by T needs to be a lot higher than the weight.

Yes.

 

[Mahavir]

Yes.

Got it, thanks a lot! :)