What to do with the shoulders during stretching of the arms in asanas?

Hi. I heard that in the warrior pose one is suppose to have the shoulders down in the back. Then I wonder about how to have them in other poses where we stretch the arms. Are they always to be kept down or should they stretch together with the arms?

It is not the shoulders but rather the shoulder BLADES that move down in Vira II.
However in Vira I/III the arms are extended. In those instances the upper arm bone (humerus) is moved toward or into the joint while the shoulder BLADES facilitate the extension (of the arms).

Generally speaking the humerus should always be kept “in joint” and therefore actions of lifting, aspiration, reaching, or creating shoulder joint safety are facilitated by finding the movement in the shoulder blades. This is of far greater concern when the arms are weight-bearing as they are in Adho Mukha Svanasana, Phalakasana, Chaturanga Dandasana, Ashtanga Namaskar, Sirsasana, Adho Mukha Vrksasana, etc.

Thank you. The only thing I understand of this is the first sentence and your last point. I guess I have to keep asking. I am not that good in understanding English. I think it is sad that the shoulders almost never are mentioned during yoga class.

The shoulders are a joint. A flimsy joint. This allows the arm to do so many things. However it also requires more for safety.

The shoulders and the shoulder blades are not the same. They are different parts of the anatomy. And in my teaching both are mentioned frequently. No sadness.

It’s not a simple topic and should be addressed by the student’s well trained teacher.
Simply put, the upper arm bone should not be extended or reached out of the joint nor should the upper arm bone be rotated out of joint.