# Planes of motion for the elbow and shoulder

lioric
1. Homework Statement

This is an olevel question from paper 5090 may/june 2012 paper 12 question number 24 (the snapshot is from another question paper) the answer in the marking scheme is A which clearly I cannot understand. I thought shoulder joints have 3 planes of movement

## Homework Equations

No equations theory question

## The Attempt at a Solution

I believe that the shoulder is a ball and socket joint which has 3 planes of movement
I don't get why the marking scheme says A

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Homework Helper
"Planes of movement" seems a bit ambiguous.
I would describe it as degrees of freedom.
The shoulder has two degrees of freedom. It is able to move a point on the upper arm along a two-dimensional surface - in particular, along a section of the surface of a sphere.

lioric
"Planes of movement" seems a bit ambiguous.
I would describe it as degrees of freedom.
The shoulder has two degrees of freedom. It is able to move a point on the upper arm along a two-dimensional surface - in particular, along a section of the surface of a sphere.

But wouldn't this be more appropriate
Flexible and extension occur in sagittal plane, adduction and abduction occur in medio-lateral axis, medial rotation and lateral rotation occur in transverse axis. So, shoulder joint is a triaxial joint and there are three planes of movement

lioric
But wouldn't this be more appropriate
Flexible and extension occur in sagittal plane, adduction and abduction occur in medio-lateral axis, medial rotation and lateral rotation occur in transverse axis. So, shoulder joint is a triaxial joint and there are three planes of movement

Also look at the examines report for biology 5090 oct nov 2012 paper 3

It says that shoulder has 3 planes of movement
Now I'm confused

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Mentor
I am not sure about your sources and, like @.Scott answer exemplifies, you need to consider previously defined terms.

As presented you are correct - 3 planes - x, y, and z. Period. There is no other answer unless the definitions given differ. Or the base question makes assumptions I cannot see.

Studying old exams is NOT always a short cut to success. If this was on a standardized exam, it had a fixed set of expected and required sources - textbooks or whatever course material (or syllabus ). So, if you do not know or cannot know the prerequisites, then poring every every detail in every answer is going to cause confusion. You are confused, right?

lioric
I am not sure about your sources and, like @.Scott answer exemplifies, you need to consider previously defined terms.

As presented you are correct - 3 planes - x, y, and z. Period. There is no other answer unless the definitions given differ. Or the base question makes assumptions I cannot see.

Studying old exams is NOT always a short cut to success. If this was on a standardized exam, it had a fixed set of expected and required sources - textbooks or whatever course material (or syllabus ). So, if you do not know or cannot know the prerequisites, then poring every every detail in every answer is going to cause confusion. You are confused, right?

I'm confused because I know it's 3 planes but the answer says two
I know my syllabus and the theory
But when a standardized test paper say something different I became confused.
Btw this is not to study for an exam but a question a student brought to me because of the conflict due to the answers of the paper

I just wanted to know if either of you guys saw something in the question that I did not see.
I'm happy to see that I'm on the same page as you guys
Thank you

jishnu
1. Homework Statement
View attachment 227151

This is an olevel question from paper 5090 may/june 2012 paper 12 question number 24 (the snapshot is from another question paper) the answer in the marking scheme is A which clearly I cannot understand. I thought shoulder joints have 3 planes of movement

## Homework Equations

No equations theory question

## The Attempt at a Solution

I believe that the shoulder is a ball and socket joint which has 3 planes of movement
I don't get why the marking scheme says A
I don't know whether my knowledge would be enough to answer this question
But, logically speaking I have drawn the possible plane of motion(don't know whether I have missed anything) for the shoulder and the elbow.
The shoulder is movement is restricted to 2 planes and I think the ability of our shoulders to rotate does not necessarily add another additional plane of motion since it rotates itself on the same plane.
I really don't know if that makes any sense.

Sent from my Redmi Note 4 using Physics Forums mobile app

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lioric
lioric
I don't know whether my knowledge would be enough to answer this question
But, logically speaking I have drawn the possible plane of motion(don't know whether I have missed anything) for the shoulder and the elbow.
The shoulder is movement is restricted to 2 planes and I think the ability of our shoulders to rotate does not necessarily add another additional plane of motion since it rotates itself on the same plane.
I really don't know if that makes any sense. View attachment 227182

Sent from my Redmi Note 4 using Physics Forums mobile app
So I guess it's like the analog stick in the joypad
It is a ball and socket joint and the analog stick has x axis and y axis but the rotation is not an axis
Thank you very much

jishnu
So I guess it's like the analog stick in the joypad
It is a ball and socket joint and the analog stick has x axis and y axis but the rotation is not an axis
Thank you very much
My pleasure, hope that helps you[emoji4]