Drum&Bass said:
what is actually "rotating" ????? all those muscles you mention pull back, you need your chest to press forward and the lateral part of your shoulders for elevation.
This is a false statement. Upper arm movement is a combination of chest, shoulders and upper back muscles.
Most neglected
Neck
obliques
Serratus
Grip
Long tricep
calves
Upper arm movement is obviously very complex and is obviously a combination of those things, yes. However, I never once mentioned movement, I mentioned ADDUCTION and ABDUCTION. These are both done largely via the Teres muscles with some bit of assistance from the bigger groups.
If you hold your arms out straight from your sides so that you look like a T:
- Bringing them in front of you into a Superman pose is done by the Pectoralis group.
- Bringing them from this pose back to the T pose is done in part by the Posterior Deltoid, Lateral Deltoid and the Lats.
- Bringing them up above your head so that you look like the letter I is done by all three Deltoid muscles.
- Bringing them down from there is done by the Latissimus Dorsi.
- Rotating your palms in a T pose so that they face upward/downward is largely done by the Teres muscles.
Of course other muscles become stimulated during these movements, it's natural that happens because of stabilization and adjustments.
This is why I never use the term 'rotating' if I can avoid it. It's a very general term considering there's 6 directions (3 main axes x 2 for moving each direction in those axes) for any ball joint to rotate in: Adduction, Abduction (rotation around the X axis) Elevation, Depression (rotation around the Z axis) Retraction, Protraction (rotation around the Y axis).
I've been studying anatomy at this point for several years. I have been doing sculpture and life drawing for 3-4 years now. I have been doing character animation for 2 years. I feel like I'm a reliable source of information.