His shoulders straightened when he saw who was calling.
As he reached the door I saw his shoulders straighten.
He took up his glass, and his shoulders straightened again.
Vicki took a deep breath, and her shoulders straightened as though a weight had lifted.
Monk's shoulders visibly straightened and he almost took a step forward.
He stood at the head of the table, then after a long second, straightened his shoulders.
I saw Ouse's shoulders straighten, almost as if he were about to rise and speak in answer.
Ape rose, suddenly little shorter than me as his shoulders straightened.
Her shoulders straightened as if she'd slammed steel poles into them.
I saw his shoulders straighten and then he turned around to face me.