relationship of muscles during pronation and supination

Question 1

What are the position of the radius and ulna while supinated?

Answer 1

parallell
radius is lateral
ulna is medial

Question 2

How does the radius spin in pronation?

Answer 2

the radius head spins on its head proximally

the distal radius spins around the head of the ulna

Question 3

What is the position of the radius and ulna in full pronation?

Answer 3

the radius is crossed over the ulna at the distal end

at the proximal end the radius and ulna position does not change

Question 4

What is the purpose of the interoseus membrane?

Answer 4

1) holds ulna and radius together
2) separate the flexor and extensor compartment
3) transfer power from radius to ulnar when pushing with hand
4) act as a muscle attachment for deep flexor and extensor MM
5) have sufficient flexibility to allow pronation and supination movements while still performing its other functions