Chair based urdhva Dhanurasana is the icing on the cake from the sequence of backbending asanas....to get a deeper stretch ,i spread my arms horizontally on the wall behind,( keeping the chair little closer to the wall) and,then bringing the palms shoulder width apart....at the same time keeping the pelvis lifted....and,maintaining the elevated pelvis....it's magical!God bless 🙏😊
It depends upon how mobile your elbows are and if there is a tendency to hyperextend or there is a strong 'carrying angle'. It's not that you intend to face the inner elbows forward however if you intend to face them inwards this may restrict your capacity to roll the shoulder tips back. Make rolling the shoulder tips back and engaging the shoulder blades down the back a priority and then offer restraint at the inner 'chip' of the elbow (ie when you look down at your inner elbow the inner 'chip' is the bit closest to you).